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It started out innocently enough.
Well—no. Actually, it really didn’t.
See, Katsuki knows Deku is his omega. History aside, it’s Katsuki who left pup-bites on Deku’s neck and wrists when they were just brats, and who bumped rudely into Deku’s shoulders in middle school just for any excuse to touch and scent him. Their days at UA saw their relationship improve, and Deku stopped hiding his obvious admiration and the way his gaze lingered on Katsuki. Good. Katsuki became better, too—pushed himself to apologize, to be there for the nerd as a rival, a classmate, a friend. Whatever Deku needed, whatever he wanted.
They’ve been rooming together since graduation, Katsuki not-so-subtly wanting to keep the nerd close. They already shared a workplace, a hometown, a friend group—an apartment was a logical extension. It’s painfully good, domestic in a way that makes Katsuki’s heart throb and his teeth hurt from how sweet it all is. When Deku is sleepy on the couch he leans into Katsuki like a needy cat. He wears Katsuki’s t-shirts on laundry day. Deku eats what Katsuki makes for dinner, chirps out “welcome home, Kacchan!” when he’s back from patrol like a cute housewife. To an outsider, they’d seem mated already.
But when they’re about to turn 22 and Deku still hasn’t popped as omega, Katsuki’s patience is wearing out.
Biologically, Deku is a beta—but the idiot ate All Might’s hair to magically gain a fuckin magician’s hat of quirks, and Katsuki’s had his heart impossibly stitched back together from smithereens. Biology doesn't mean shit.
Katsuki has waited long enough, and he’s not blind to the way Deku blushes and squirms around him sometimes. The nerd likes him back, even if he seems dead-set on not acting on his feelings.
Plus, well… Katsuki has become a better person, whatever, but he’s not above exploiting Deku’s obsessive admiration for him.
What the idiot doesn’t know won’t hurt him. At least, not in any way the freak won’t enjoy.
Heh.
So Katsuki amps up the casual-yet-heated touches between them. Starts resting a hot hand on Deku’s lower back to brush past him. Ruffling those fluffy curls whenever he can. Walking closer beside him at work, at home. The physical proximity lets Katsuki more heavily spread his scent on Deku, something he’s needed to do for a while. The nerd’s gotten objectively hotter as they’ve grown up, outgrowing his puppy phase and still-developing muscles to become a fucking sexy little twunk. Beta or not, Katsuki sees the creepy stares Deku gets; knows about the dozens of forums and subreddits dedicated to how fuckin’ breedable his hero partner is.
Horny extras aren’t wrong, but Katsuki is damn tired of not being able to stake a full claim—skeezy fuckers need to know that Deku is his, and his alone. Now, Deku is starting to smell more and more obviously of Katsuki, every day and wherever they go. Good.
Katsuki starts making him extra food and bringing home little treats and gifts, too. One day a bakery cupcake that looked like a fluffy white sheep. The following week, an unlicensed All Might keychain that read “PLUM ULTRA!” in butchered English (okay, he got one for himself too, it was fuckin’ funny).
All of it makes Deku go starry-eyed and blushy, stuttering out thank-yous and looking fawning and pleased and obnoxiously cute. But his beta nose is shit, and the food and gifts don’t register to him as providing and courting.
Eh—doesn’t matter. Katsuki’s got other plans.
-
Izuku doesn’t know what to do. He’s objectively and totally freaking out.
Er, not necessarily for bad reasons… but…
Well, Kacchan has just been different lately. Not exactly gentler, not exactly nicer, but—more doting, somehow. Sweeter, even if it’s tempered by Kacchans ever-present spice. The teasing and insults haven’t let up at all, but it’s different.
Izuku can’t exactly pinpoint it, but regardless—his heart can’t take much more.
Kacchan has been making him protein smoothies every morning, and they’re so good. Yesterday afternoon he even asked for a second one, which just made Katsuki smirk and oblige very willingly. Dinners lately have been a lot of creamy, heavy food, too: butter chicken curry, pureed squash soup, pasta alfredo with steamed veggies. It’s all delicious, so Izuku almost slaps himself when he asks Kacchan about it while Izuku is cleaning his plate of the last bits of that night’s mushroom risotto.
“Wanted to try some new recipes,” Kacchan shrugs, looking back at him intently. Izuku blushes, a little embarrassed that Kacchan just caught him licking his fork clean. “You don’t like ‘em?” he asks, blinking slowly.
“The opposite!” Izuku blurts out. “They’re really good—I keep craving more, honestly,” he says, face red. Maybe that was too much information. After all, until recently Izuku didn’t exactly consider himself someone who liked such rich food. But he goes to bed feeling warm and fuzzy and satisfied after Kacchan’s dinners lately. The feeling is addictive. Sometimes he swears he feels the flavors in his mouth even long after the meal, making him hungry all over again. Kacchan apparently isn’t too offput by Izuku’s impulsive response, because he just smiles at him, a slash of a grin set in his handsome face.
“Good,” he says, stretching his legs out casually under the table. One of his socked feet knocks lazily against Izuku’s. “I’ll keep you fed, then.”
Izuku smiles back, wobbly and pleased, and starts gathering their plates into the sink just for something to do, hiding his blushing ears. Kacchan is too much sometimes.
Of course, Izuku’s obsessive brain can’t stop him from grabbing his laptop, opening a new private browsing tab, and assaulting google with frantic and ridiculous searches. He spends a good fifteen minutes on a wikipedia spiral, genuinely half-convinced that Kacchan might have a brain tumor that’s altering his behavior and mannerisms (it can happen!!).
He snaps himself out of it when he realizes that he’s clicked through so many successive hyperlinks that he’s somehow landed on a page about the history of modern art in Thailand. Super interesting, but so far off topic. He bookmarks the tab for later. Gah—focus, Izuku!
Ack. Okay. Finally, because he’s dense but not that dense, and with a red face for even thinking about it, he types in:
Alpha courting gestures
The results he steadily clicks through are… illuminating. Most of it sounds a whole awful lot like how Kacchan has been acting towards him lately—the increased closeness, the food, the little gifts and gestures.
Something in Izuku can’t quite believe what he’s reading, how it might match up to reality. Kacchan could have anyone he wanted. He’s an alpha; a strong, handsome one. Izuku isn’t that down on himself—he’s had plenty of offers, and he knows he’s decently attractive. Ochako once showed him some thirst tweets from his more, er, enthusiastic fans—to her own giggling delight and Izuku’s mortified horror. That was illuminating, to say the least.
But with Kacchan… it’s hard to believe he’d be interested in Izuku, of all people. Plus—Izuku is just a boring, plain beta. When he turned 18 and hadn’t presented as anything, he made sure to see a specialist just in case anything was wrong (and because starting at Endeavor’s agency meant he needed to undergo mandatory and extensive sets of physical exams and tests).
Izuku’s samples came back ‘inconclusive’—not specifically beta, but the specialist told him that about ½ of all technically beta people get ‘inconclusive’ on their tests. Izuku didn’t really understand the more detailed explanation he was given after that, filled as it was with medical jargon. The doctor said there was a chance that Izuku could present late, but it was very miniscule.
They also explained that with his inconclusive result, Izuku would probably be especially receptive to hormone and pheromone replacement therapies, if he wanted to transition to alpha or omega. Modern medicine made it pretty easy, apparently. Izuku easily declined at the time, honestly fine with his beta status—no need to worry about heats or ruts or invasive pheromones clogging up an extra-sensitive nose. His opinion on that hasn’t changed.
Sometimes, though—like now—he thinks about it. Not about being an o-omega, but… about being Kacchan’s omega. Being able to nuzzle and purr at him, to inhale his sweet and smoky scent in all its glory…
Well, and of course, the less wholesome thoughts creep in. A brazen, drunk Aoyama once dreamily told him that sex during his heats were better than baked brie (extremely high praise, coming from him). At the time, Izuku had blushed strawberry-red and pushed a tall glass of water towards his former classmate, resolutely trying not to think about how it might feel.
Izuku has only had sex a couple of times; both hookups, brought home from the bar while Kacchan was out of town. The guys were fine and all, but Izuku is sick in the head—he kept his eyes closed the entire time, imagining spiky blonde hair and familiar red eyes in his bed instead. Would Kacchan be gentle? Izuku hopes not—Kacchan isn’t Kacchan without some fire in his veins. He can picture fangs sinking into his skin, blazing hands bruising his hips, harsh words whispered against his ear. Ah…
Izuku groans into his hands and shuts his laptop, resolutely turning off his bedside lamp and burrowing under the covers. It takes a long time for sleep to find him, and all his strength not to slide a hand into his sleep shorts and let the fantasies creep back in. It wouldn’t be the first time.
Ugh. He’s such a creep—what would Kacchan think of him?
–
Fucccccckkkkkkk.
Katsuki has barely bid Deku goodnight in the hallway before he has a hand down his pants and a tight fist around his aching cock, using his leaking pre to jack himself fast and dirty.
He can still feel the warmth and tiny bit of tacky drool on his bare shoulder from where Izuku conked out against it while they watched a movie. Katsuki had taken the opportunity to run warm hands up and down Izuku’s back and bury his nose in the nerd’s hair, inhaling the smell of cheap strawberry shampoo and Deku’s slowly-unfurling scent.
A bit of that lingers on Katsuki’s skin, too—a hopped-up version of Deku’s normal, faint -but-addicting scent of balsam and cedar and honey-mint. It’s a bit sweeter and stickier, too—a sign of an omega on the cusp of bloom. Soon.
Things are definitely falling into place. The nerd has been all cuddly and cute lately, keeps walking around the apartment in tiny shorts and Katsuki’s clothes even when it’s not laundry day, hoodies and t-shirts that he plucked right out of Katsuki’s dirty hamper. Katsuki raised an incredulous eyebrow the first time it happened, and Deku sputtered out a frantic excuse that he didn’t realize, oh my god I’m so sorry Kacchan I’ll put it back I’m not sure why I did that?!— but Katsuki cut him off, saying he didn’t mind. Deku nodded in mortification, but tellingly, he didn’t change. Katsuki has caught him a few times pulling the collars of Katsuki’s tank tops towards his face, inhaling his burnt-caramel-campfire scent and fluttering his eyes.
It’s all subconscious, clearly. At work Deku seems sharp as ever, but once they’re home, in their shared and comfortable space, filled with both their scents… Deku just goes loopy.
Katsuki keeps coming home to Deku snoozing on their sofa, wrapped up in blankets even though it’s summer. Katsuki croons in victory when he notices that one of them—a knitted dark-gray throw—is from his bed. Increased drowsiness, nesting behavior, scent-stealing from a chosen alpha… it’s all textbook.
Not to mention just how much of Katsuki’s cum Deku has been eating.
Katsuki bites at his bottom lip hard, thinking back just a few hours to how sinful and sweet Deku looked, humming happily and rubbing his belly after he scarfed down his dinner of sweet and spicy coconut curry.
Over the past month it’s become second-nature to fuck his fist in their kitchen, stifling groans as he closes his eyes and imagines what it’ll be like when he can finally feed Deku right from the source. The nerd would stick his little pink tongue out, wiggling it enticingly and whining and staring up at Katsuki from his knees, big doe-eyes wide and pleading. And Katsuki would give Deku exactly what he wanted, spurting hot and thick all over his cutesy little freckles and his stupid-long eyelashes, dirtying him up… fuck, fuck—it was too easy to squeeze his knot and spend a ridiculously large load into Deku’s portion, watching as his milky, potent cum glazed over the dish like a perfect garnish. Katsuki only really lets himself cum into Deku’s food these days.
Well, that and…
Katsuki grunts out a breathless noise as he stumbles over to his closet, digging through to find his stash of Deku’s clean underwear—their joint laundry days made it all too easy to swipe a few pairs. Katsuki only needs a few more strokes before he cums, making sure to spend all over the fabric. He milks his sore knot with small flexes of his fist, watching as his cum soaks into the white cotton. He’ll give them a bare-minimum rinse and dry: just enough so a stain doesn’t show, but not so as to completely erase the seeped-in scent of cum. Katsuki’s cum. He’s been sneaking the pairs back into Deku’s drawers when their work schedules don’t line up, and Deku hasn’t batted an eye. God, Katsuki could get hard again just thinking about how his dumb, unsuspecting nerd has been wearing tight little briefs marked and scented with Katsuki’s thick cum.
Soon he’ll have his omega wearing boyshorts and pretty panties, and Katsuki will drag him aside every morning to cum in them, fuckin’ soak the fabric through, just to tuck them back around Deku’s pathetic cock and send the nerd on his merry way… fffffuck. Katsuki grits his teeth, willing away the surge of heat and the impulse to just sneak into Deku’s room and have him now.
Soon, he reminds himself.
Katsuki falls into bed, already really looking forward to next weekend.
–
Izuku feels great.
The last few weeks have been amazing, and to top it all off, today is his birthday. Usually he just works, maybe hangs out with a friend or two. Last year he and Shouto were on a mission in Korea, and all he did was briefly facetime his mom and polish off… an inadvisable amount of really nice soju (a gift from their partner agency).
He and Shouto watched a trivia game show on the hotel TV until two AM, trying to blurt out the right answers and shouting over the TV presenter. Notably, neither of them speak Korean. That was really fun, actually.
But this year, Ochako and Yaomomo and Kacchan (!!) helped coordinate a big surprise group for dinner and drinks. Izuku gasped in delight at the turnout as he and Kacchan arrived at the private room, their rowdy former classmates whooping and hollering and shouting out cheers. The night passed in a blur of delicious food and much-needed catching up with his friends, some of whom he hadn’t seen in ages. Hero work keeps them all crazy busy. Izuku only cries a little bit at the happy, cheerful mood and the warmth of so many loved ones in one place.
… Okay, he blubbered like a baby about three separate times and everyone made fun of him for it. He’s been emotional in general lately, give him a break. And he just feels so lucky!
The night is a far cry from the depressing celebrations of his youth, or the birthdays he “enjoyed” at UA (one spent on the lam from villains, the other two in hospitals with at least one major internal injury). Seeing how much his life has changed, where he is now… it still makes him feel like he needs to pinch himself, to make sure it’s not a dream. If only 12-year-old Izuku could see him now: laughing and eating with his closest people, living his dream as a hero, sitting next to Kacchan (who’s ribbing him about ordering katsudon). The road to here hasn’t been easy, but he’d do it all over again in a heartbeat to be where he is now.
By the time everyone is hugging their last goodbyes and stumbling home, the other bars along the street are already shuttered. Izuku feels warm and happy, all bubbly inside like the glasses of champagne they all shared. Kacchan huffs out half a laugh and loops an elbow around his.
“Don’t fall over, tipsy nerd,” he says. “You had like three bottles of plum wine, I can’t believe you’re even standing upright.”
“Ultra fast metabolism—I blame One for All,” Izuku sighs, smooshing the side of his face against Kacchan’s upper arm. Mmm, Kacchan’s biceps… so firm, yet squishy. Ideal headrest. He must have said that out loud, cuz Kacchan barks out a laugh, and Izuku savors the echo of that sound all the way home.
Before long they’re toeing off their shoes in the genkan, and Kacchan pads away in the kitchen, presumably to put away the leftovers from dinner. Izuku is about to flop down on the couch when Kacchan calls him over, and Izuku perks up to follow.
“Surprise number two,” Kacchan says, turning around and setting down a beautiful cake on their countertop.
“Oh my god, Kacchan, this looks amazing! Is it strawberries and cream?” he asks, moving his head around to look at all the lovely red fruit placed decoratively around the dessert. There’s some sort of—translucent gelatin?—set into the strawberries crowned on top, making them look extra glossy and delicious. Kacchan grunts an assent to his question, already using one of their kitchen knives to cut Izuku a slice.
Ah man, Izuku’s mouth is watering—it looks so good, honestly. He probably looks like an eager puppy waiting for kibble as Kacchan plates up a slice and pushes it towards him. Izuku doesn’t bother to wait even a second before he gathers a generous bite onto his fork, making sure to scoop up plenty of the gleaming, gelatin-coated strawberries that sat on top.
“S’ho good, oh my god,” Izuku moans, closing his eyes to really savor it. The gelatin adds a nice little salty creaminess, cutting the sweetness of the buttercream and complementing the juicy berries. Izuku gushes as much to Kacchan, who rolls his eyes fondly.
“Jesus, make sure you chew and swallow—if you choke I am not giving you the damn heimlich,” Kacchan says. Izuku just grins back at him, mouth still half-full as he goes in for another bite. Kacchan definitely would give him the heimlich, so he’s free to basically inhale his treat. Izuku tries to needle Kacchan into trying a tiny bit, too, but Kacchan waves him off and says he’ll have some tomorrow. Izuku hums in concession; Kacchan has mentioned that he never sleeps well if he has sugar right before bed.
Izuku polishes off his cake, and as it settles in his stomach it hits him how sleepy he is. Kacchan must have noticed, because he pushes him towards the bathroom with orders to brush his teeth and go to bed already. Izuku complies sleepily, making sure to thank Kacchan again before he follows his marching orders. As soon as his head hits the pillow, Izuku is out like a light, smile still lingering on his face. He feels warm and oh-so-full.
Katsuki wakes up with a start, instincts pricked in immediate alarm. There’s pressure pinning his legs down. His palms are already hot and sparking, ready to address a threat, and he rears up to see—
The limned outline of messy green hair, muscled shoulders. Way too familiar, even in the dark.
“The fuck?” He rasps out, slapping a hand on the switch on his wall to turn the bedside light on.
And—holy shit, Deku is a sight. Flushed a delicious pink, wet mouth open and panting. He’s wearing nothing but a stupid shirt and tight briefs, and Katsuki—holy shit, fuck—can feel wetness on his upper thighs, right where Deku’s sitting.
“Kacchan,” he says breathily. “I’m—I’m sorry, I feel weird, I felt like—I had to come to you—“ he hiccups against an overwhelmed sob.
Katsuki doesn’t think before he’s banding his arms around Izuku’s waist, pulling his nerd close and burying his face into his blushing throat. A deep inhale makes him groan—goddamn but he smells like sin, lush and wet and fertile like fresh earth.
“Shit, Deku—it’s okay, baby boy, I got ya,” he rumbles into his skin. Katsuki gives in to what he wants, licks a fat stripe up the pulsing gland in front of him, sucks and teethes at it gently. Deku reacts beautifully, arching his back and whining. Shit, shit. Katsuki’s patience has paid off tenfold—he never expected it to be so effective, but here’s Deku in his lap, clearly on the cusp of a full-blown presenting heat. His Deku is really something. Katsuki’s inner alpha howls with glee, and it’s all Katsuki can do not to pounce and ravage Deku immediately.
Instead he moves his face to nuzzle comfortingly into Deku’s skin, streaking his familiar scent all over his new omega. He rumbles soothingly, using the pad of his thumb to rub steady circles into the gland at the other side of Deku’s neck. His other hand runs soothingly up and down Deku’s shivering back. The steady, calming motions seem to be helping, because Deku’s whimpers are beginning to sound more like pleas than distress calls. He rocks his hips gently down against Katsuki’s legs, smearing him with fragrant slick. Katsuki feels his mouth water, fangs itching.
“Kacchan, please, c’mon—I don’t know why, but I need—” Deku cuts himself off, dropping his head and letting out a squeaky purr as Katsuki peppers kisses higher up to lavish attention on the hinge of his jaw and his red, freckled cheeks.
“What d’you need, De-ku?” Katsuki asks. He may be disgustingly gone on the idiot, but he can’t help still being just a little mean, a little teasing. It’s in his nature. Deku glares at him, somewhere between annoyed and desperate.
“Need you,” the omega hisses out, his broken purrs stuttering and stopping as he continues to rock down into his seat and lean into Katsuki’s attention. His movements stutter whenever Katsuki’s fangs tease at his sensitive neck. Katsuki grins into the skin at Deku’s throat, laying down a last lingering mark before drawing back. He’s barely done anything and Deku’s a shivering, shaking mess.
“Beautiful,” he murmurs. Deku blinks, eyes gone wide and dewy before he buries his face in Katsuki’s chest. His scent is billowing out in tumultuous waves, giving him away entirely—awed, confused, excited, horny as fuck. Deku is wet enough now that Katsuki’s pants are sticky in his lap, and the air smells damn irresistible. Katsuki makes sure his scent is broadcast in turn—he wants Deku to know just how good Katsuki feels about this new development. It must be clear enough even to Deku’s untrained nose, because the air sweetens impossibly more, and Deku noses deeper. Like he could bury himself in Katsuki’s skin, if he tried.
Katsuki prods at Deku until he can rearrange them, pushing the nerd into the mattress and shifting to loom over his omega. Deku is built like a brick shithouse, but Katsuki is just that bit bigger and broader—it makes Deku look sweetly vulnerable underneath him, staring up at Katsuki all pink and pleading as he just keeps leaking all over himself. The sight makes Katsuki pant like a damn dog, dick so hard it’s straining at his waistband.
Deku doesn't seem content to wait idly by—his hands paw at Katsuki’s waistband, and Katsuki lets Deku pull it down and stroke light fingers up and down his shaft. The nerd rubs a thumb experimentally around the dripping head, eyes wide as he licks his lips and glances between Katsuki’s twitching cock and his face to assess his reactions. Katsuki groans and bucks into it, letting Deku know how good it feels.
Katsuki lets his boy explore, running those knobbly hands all over Katsuki’s chest and abs, stroking his cock with increasing confidence, squeezing his fist around the growing knot on each downstroke. Katsuki hisses and swallows down drool—the touches are hardly anything, but he feels deliriously turned on, dangerously close already like he’s a rutting pup all over again. All his pubescent fantasies starred the idiot, so really, it’s not surprising. Katsuki practically conditioned himself to wanna cum at the sight of Deku like this, underneath him, touching Katsuki all reverent and determined.
Fuck. Katsuki shakes himself and pushes Deku back down, gripping the omega’s wrists in one hand and using the other to pin him by the chest. Deku squawks, upset to be interrupted in his fawning, but Katsuki shuts him up with a bruising kiss. He takes advantage of Deku’s captured hands to take his own fill.
It’s… illuminating. Katsuki learns that Deku has a sensitive chest, tiny tits swollen a little with his first heat. The nerd squirms and keens and leaks as Katsuki bites meanly at his nipples, licks over and over into the thin skin at his sternum and above his ribs. He finds out that running a trimmed fingernail lightly up the shaft of Deku’s short, thick cock makes him wail and shudder. Katsuki mercifully releases his grip on Deku’s wrists, and when Katsuki shifts down and swallows his omega’s whole length into his throat, Deku buries his hands in blond hair and lets loose a rasping shout.
It all makes Katsuki croon in delight, and the hearty vibrations in Katsuki’s throat just drive Deku further towards the edge. Incredible, Deku is fuckin’ incredible. Saccharine-sweet and responsive and surprisingly greedy—no reservations about chasing his pleasure, about pulling and pushing Katsuki by the hair to demand more. Katsuki wouldn’t want it any other way; no way fierce, determined, Deku-who-does-his-best would be a pillow princess. Katsuki catalogs every reaction, stores away every hitch of breath and stuttered moan. He wants to know exactly how to drive his omega wild, over and over again till they’re both spent.
Deku’s hips bucking into the heat of Katsuki’s mouth is getting more off-pace and intense—and oh, that just won’t fuckin do. Katsuki draws away, a string of pearly spit momentarily connecting his lips to the flushed head of Deku’s cock. The idiot lets out a pathetic whine, dick bobbing and needy, his face pouting and red.
“Easy—I don’t want you coming until you’re on my cock,” Katsuki rasps out. Deku groans, nodding like a bobblehead and spreading his thighs like it’s just that easy. Katsuki exhales harshly—the skin there is blushing and freckled, shining with strings of slick leading up to his wet hole. Deku runs one scarred-up hand along the crease of his thigh, fingers teasing wonderingly at his ass. He seems torn between hunger and disbelief at just how drenched he is.
Katsuki bats away Deku’s hand and runs a gentle palm through the mess of slick, circling his fingers around Deku’s rim before dipping inside. Deku knocks his head back and sighs, wriggling his hips to encourage Katsuki to fuck deeper, slicking his fingers every time he draws out just to drive in harder. Katsuki’s up to four fingers in a span of what feels like breaths, and Deku takes it like a champ.
It’s gross and sappy, but Katsuki can’t look away from Deku’s face. No use denying it; Deku is goddamn gorgeous like this. Katsuki knows must be saying as much, babbling sweet filth at Deku, but the blood is pounding in his head so loud that he doesn’t even know what words are pouring out of his dumb mouth.
Whatever it is, Deku seems to like it. Good—the nerd’s pink cheeks bring out the vivid, watery green of his eyes. When Deku flicks his gaze up and catches Katsuki’s eyes, he gives Katsuki a wobbly smile and brings his arms up to circle around Katsuki’s nape. Katsuki makes sure the idiot doesn’t see him grin dopily back, but based on the little giggle Deku lets out, he can feel Katsuki’s smile against his lips as they drag each other down into a series of slow, searching kisses. Katsuki keeps stuffing Deku with his fingers, curling and searching until Deku gives a punted-out moan against Katsuki’s mouth. He found a good spot.
“Kacchan, fuck—in me, don’t make me wait,” Deku pants out after a few minutes of steady abuse on his prostate. His breath is warm and sweet against Katsuki’s cheeks, and something about how intimate that is makes Katsuki shiver and swallow hard. He draws back reluctantly, pulling out his sticky fingers to a downright mournful noise from Deku. Katsuki snorts, swatting his omega’s wet thigh to a squeal and giggle from Deku.
“Brat. Hold onto something,” Katsuki says. Deku gets him back by choosing Katsuki’s back to latch onto, digging his stubby nails into the skin and grinning dreamily. Katsuki’s heart stutters again—damn the nerd for being so cute even while he’s leaking like a cheap slut and gagging for cock.
Katsuki’s dick is fucking aching from being neglected for so long, and he fists it tight as he feeds the head into Deku’s waiting, winking hole. Fuck—he keeps his hand clamped around the base, staving off the urge to just bury himself and cum in one thrust. “Sucking me in so good, Deku, goddamn,” he groans.
“Kacchan,” Deku grits out. Katsuki tears himself away from the sinful sight of Deku’s hole taking him like a dream. Deku’s eyes have that gleam in them that means he’s about to raise hell, and Katsuki hardly has time to react before Deku shoves his ass down and buries Katsuki to the hilt inside him.
Katsuki makes an embarrassing noise, nearly drowned out by Deku’s pleased and bubbling chirps and purrs. He looks adorably confused about all the new omega noises pouring out of him, but Katsuki’s heart swells knowing the meaning. He can’t help how his hips start rolling to meet Deku’s motions. They work up into a rhythm that’s deep and sinuous, arching indulgently close even as the arousal roars like sparks between them. Weirdly, the desperate rush has tumbled into a searing feeling that makes Katsuki want to take it slow. He still stuffs Izuku hard; pushy and mean when he sinks in deep, but he takes his time. He folds Deku damn near in half, pushing the nerd’s ankles to his ears ‘cuz he knows Deku can take it. He grinds his cockhead right into Deku’s prostate on every thrust, watching with dangerous awe as each deep stroke makes a subtle bump behind Deku’s lower stomach. Deku notices, too—he cranes his neck forward and makes a wounded noise, running a hand worshipfully over the swell and pushing down on it lightly.
The added pressure makes Katsuki groan and buck hard into Izuku’s tight heat, and Izuku lets out a slutty little cracked-up shout—music to Katsuki’s ears. Katsuki does it again, and again, and again. Whatever banked embers from before have reignited, now a consuming blaze, and their easy pace is abandoned in favor of desperate fucking.
Katsuki can’t stop his rabid thrusting, bending Deku even further until he’s supporting his omega’s thighs against his torso and Deku’s cock is bobbing and leaking right above his own face. Deku fucking loves it, if his noises are anything to go by—punched-out screams tearing from his throat, trailing into overstimulated hiccups and gasps. Deku’s cutesy face is stained with drool and tears, eyes lidded and fixed on Katsuki just like they should be. Deku’s insides pulse around him like a silk vise, milking greedily at Katsuki’s thick cock and swelling knot. It’s goddamn obscene, seeing Deku’s flushed little hole stretch around the bulge as it grows and grows.
Katsuki’s not sure he can hold off that much longer. It’s a miracle he’s lasted this long at all, really—Deku is so goddamn hot like this, meeting Katsuki’s thrusts and urging him on harder with ankles around the small of his back and blunt nails digging into his shoulders.
It’s Deku’s desperate demands for Katsuki’s knot that really send him over the edge—the little whore just keeps crying for it, even as Katsuki’s thrusts lose their steady rhythm and the swell is almost too big to pop back out once Katsuki bullies it in. Katsuki grits his teeth against the sizzling pleasure, thrusting brutally and pratically knot-fucking his omega as he nears the edge.
“Kacchan, fill me up, fuck, please, wanted this forever, wanna be yours—“ Deku’s incessant babbling ratchets up the tension in Katsuki’s gut until it snaps, and he buries his cock to the root. He feels his heavy balls twitch and his dick throbs as he cums his damn brains out—fuck, and just keeps coming, seemingly-endless pulses as he fills his baby up.
He barely has the presence of mind to grab Deku’s purpling, needy cock and strip it hard and fast. It only takes a few slick tugs before Deku shrieks dryly and topples off the edge. Deku is still folded over on himself, and Katsuki watches with sick awe as the omega’s cock spills heavy across his own heaving, bulged stomach. A few spurts actually catch him across his own face, striping across his freckled cheeks and one eyelid. Debauched fucking nerd, fuck—and Deku’s ass feels impossibly good as he’s cumming, milking Katsuki’s still-spurting cock with intense internal squeezes. Omegas really are built to take cock and cum, huh.
Katsuki purrs roughly and swipes his fingers through the mess on Deku’s face, cleaning his boy up and bringing the cum to his own lips. He licks the taste of Deku off right off his hand, smirking as the idiot watches with wide, shocked eyes.
Deku seems overwhelmed—he lets his head loll tiredly to the side, whines softly and pats insistently at Katsuki’s shoulder. Deku urges him to help them turn on their sides and Katsuki hurries to oblige, tipping them both gently so he can spoon Deku from behind. He uses a strong arm to band around his omega’s waist and pull him close, heats up the palm resting on Deku’s stomach just a little and rubs at his hips, hoping to ease the twang he’s sure is present from their position. Deku hhhhmms in contentment, shoulders sagging. His hole clenches warmly around Katsuki’s cock again, and Katsuki buries his face in Deku’s messy hair as he shudders and cums again, overstimulated and high on it.
Deku purrs and shifts his hips a little, making Katsuki bite off a hiss. He keeps making these minute movements and happy little hums, and—oh, the little shit knows exactly what he’s doing. Katsuki rumbles and bites at Deku’s blushing ear, and the omega lets out a guilty giggle—but he wiggles his plush ass up against the flat of Katsuki’s hips, clearly not deterred.
“Horny little shit,” Katsuki says, shifting his grip on Izuku’s torso to something tight as he rocks his hips forward hard. Deku pushes his head back to rest on Katsuki’s shoulder, staring blearily up at him with a smile.
“More,” he says simply. And—fuck, who is Katsuki to deny him? His knot’s not even soft yet, so he just keeps a slow, rocking pace, listening to Deku’s smug chirps as he meets him halfway. It’s a sweet, cuddling fuck—made a little more frantic when Katsuki stuffs a few fingers in alongside his still-swollen knot, stretching Deku until the omega whimpers and just soaks himself, untouched, spurting weakly and arching with delicious full-body shudders.
Katsuki doesn’t give him any rest after—just rolls so he’s covering Deku’s whole body with his larger form, using his weight on top to drive his cock deeper than their other positions had allowed. Deku chokes on screams and his own drool, flattened on his stomach like a true bitch. All he can do is rut pathetically into the sheets as he takes what Katsuki gives him: harsh, bruising stabs of his hips. Katsuki cums again as he’s sloppily stuffing his knot back inside, watching his own cum froth around Deku’s rim and spill down the backs of his thighs. Katsuki’s alpha brain is officially howling with glee. Good boy. Bred and full and ours, all ours. Katsuki’s logical head can’t help but agree.
Doesn’t mean they’re done yet, though—Katsuki has oh so much more to give, and his Deku is meant to take it.
The haze of their combined pheromones and the feedback spiral of endorphins from so many orgasms makes them both loopy. Izuku forgets where he ends and Kacchan begins. They fuck all through the wee hours of the night. At some point they fall asleep, Deku’s thighs still soaked and spasming with leftover zings of pleasure from their—god, he doesn’t even know what round they were on.
Sometime before sunrise he wakes up again feeling bereft, empty, and he rolls closer to Kacchan and guides his still half-hard cock back inside him, exhaling shakily at the sensation of being full again. He doesn’t know how he’s supposed to live without Kacchan inside him after this. He settles on his still-sleeping alpha’s cock, spread open and stuffed and deeply pleased about it. After that, it’s easy for Izuku to trip back into sleep—snuggled into Kacchan’s warm skin and speared on his dick.
The morning dawns harsh and bright, and Izuku groans awake. He squints against the glare and winces as a full-body soreness hits him like a truck. A pair of strong arms rest heavy around his waist, and he feels light breaths against the nape of his neck. Despite the achiness, Izuku breathes deep and sighs out contentedly. Smells like Kacchan, and so strongly—but another scent, too, like full greenery and mint and sweetgrass.
Huh.
Oh. Right.
Right—wait.
Oh my god, did he seriously—?!?
Izuku’s memories rush back in, and he starts spiraling. Holy shit. He recalls waking up at god knows when in the night, overheating and panting and absolutely slicking through his sheets. He presented last night—though he could hardly process that insane realization through the miasma of heat and smell and want.
He tried to ignore it, to just toss and turn and eventually exhaust himself back into sleep, but his brain just got fuzzier and more desperate, crying out for some sort of relief. Izuku’s body may have been confused, in a delirious and directionless overdrive, but his new omega knew exactly what to do. Exactly what lay just down the hall, exactly what Izuku really wanted—no—needed.
And then. Oh god. Izuku actually listened to the horrible, horny little thing. He jumped Kacchan’s bones like the most shameless slut in the world. He invaded his alpha’s space and came onto him. Kacchan got on board pretty quickly, but Izuku must’ve seduced him against his own will somehow—can omega pheromones do that?!—because Kacchan wouldn’t… he doesn’t want Izuku like that, he’d never normally—
“Shut up, it’s too fuckin early for this shit,” a deep voice rasps in his ear. Izuku freezes, tensing until Kacchan starts rubbing soothing circles into his sides with his thumb. “Idiot. You didn’t even realize, huh… You’ve always been my omega—you and I both know it. I just did a bit to catch your body up,” Katsuki rumbles, tone going dark and sure. His grip tightens a bit more, and Izuku sweats at the feeling of Kacchan’s twitching morning wood pressed insistently against the small of his back.
The words sink into his dazed, sex-hungover brain slowly. Didn't realize what? And what does he mean, ‘catching his body up’? Izuku is—was?—a beta, so how could Kacchan—
Uhhhhhhhhh, oh shit. Izuku feels himself getting faint as the implications sink in, and he has sudden flashes of harried jerk off sessions, the obscene videos he’s shamefully gotten off to. The pamphlets he brought guiltily home from the secondary gender specialist, titled things like “at home hormone replacement methods for bonded mates.”
The colloquial term is much less tasteful, but Izuku feels himself squirm and start to honest to god slick as it crosses his mind.
Kacchan bitched him.
“Shoulda seen yourself, Deku. Fuck—looked so good eating my cum, wearing it all over you, my scent all on you… perfect. You were meant for it,” Katsuki continues. He ducks his head down to inhale deeply at Izuku’s throat, letting out a satisfied purr loud enough to rattle both their chests.
It should be disgusting. Izuku should be beyond horrified. He should be… he should…
Katsuki’s grip on him lightens a bit, perhaps in response to the way Izuku has gone still as a stone.
“Kacchan,” Izuku says, voice still a bit hoarse from all the screaming he’d done that night. Katsuki pauses and starts to fully draw his arms away, but Izuku snatches them back with a harsh grip on Kacchan’s wrists. He uses the leverage to turn around and face Katsuki. Izuku stares him down, and Katsuki returns his gaze evenly. He doesn’t look sorry, but there’s worry lingering at the corners of his eyes.
“You—you could’ve just asked, you idiot!” Izuku growls, using his grip to shake a wide-eyed Katsuki to his senses. “I’ve wanted you since forever, and you thought you had to sneak around?! You could’ve just fucked my face and cum right down my throat! I would’ve begged you for it for it, moron!” Izuku snaps, face blazing as he lets the truth spill out. Katsuki’s eyebrows shoot up to his hairline, and there’s a weighty pause as that all sinks in. Izuku is miserably embarrassed, but seriously, who the hell does Kacchan think he’s dealing with?! It’s not the time for modesty. Seriously, this idiot…
“Well, it’s not too late to try some new methods,” Kacchan ventures lowly. He flexes his wrists in Izuku’s iron grip, licking his lips. Izuku’s nose twitches as the sudden outpouring of aroused, desperate scent that’s rolling off his—his alpha. His mate?
Ohhh, but that sounds good. Izuku is new to all this, but the stupid, stupidly hot man beneath him is his, that’s for sure.
“Ah—later. you’ve got some real making up to do,” Izuku huffs. He knows he must be pouting ridiculously, because Kacchan croons all bassy at him, raising an eyebrow in challenge.
Fat chance.
Izuku hesitates for only a heartbeat before he exhales in a rush, throwing dignity and decorum out their nice fifth story windows. He’s riding a crazy emotional mix of giddy relief and truly depraved horniness—he deserves this.
And, hey, It turns out it’s pretty amazing to shut your alpha up by riding his face. Kacchan diligently cleans him up, and Izuku cums in delicious, rolicking waves and spasms. “Again,” he croons. Kacchan just stares up at him in a dazed awe, following orders and drinking down Izuku’s slick without argument. His whole face is pink and his eyes are glazed over. Izuku has never seen him like this—weirdly docile, tactile in the way he reverently grips at Izuku’s thick thighs. He looks downright drunk on the feedback loop of pleasure, burying his whole face between Izuku’s legs like he’s starving for it. When Izuku cums again, wheezing and overwhelmed, Kacchan licks his chops and purrs like the cat that got the cream. He looks full. Sated.
Huh. Interesting.
Later, when they’ve both tired themselves out again—and when Izuku’s gotten his fix of Kacchan-prepared breakfast, uhhh, directly from the source—Izuku peeks at Kacchan’s dreamy, pleased expression as he dozes cuddled up at Izuku’s back.
Izuku hums and closes his eyes too, idly wondering if consuming omega slick has any effect on alphas.
***