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Katsuki sighs as he closes his bedroom door. "He'd just gotten done with his monthly visit to Recovery Girl to discuss his upcoming rut. After having so many of them come up randomly and lead to embarrassingly destructive rampages around the dorm, he was required to check in with her before every rut for a healthy dose of anti-rut aggression meds for him to take before the rut hits.
And as embarrassing as it was, the sight of the small chewable tablets helped Katsuki’s mind ease the bundle of raging hormones his pre-rut always caused. Popping one of them into his mouth, he hums slightly at the sweet orange taste. He would normally prefer something spicier, but Recovery Girl had said that they haven’t managed to make spicy medication.
The effect is almost immediate as Katsuki’s shoulders relax and his mind stops racing.
“Finally,” he mumbles to himself as he moves around his room, putting away anything that may get broken or blown up in the coming daze. It only takes a few minutes to do so, with Katsuki having done this a number of times by now, and when he is done it feels like he can breathe deeper.
Just as he is about to sit down and relax, there is a knock at his door. With a deep sigh, he stands up to answer it, not surprised in the least when he sees his best friend and 3-year-long crush standing there.
“Hey, Bakugo. I brought up some pizza for you. I know you don’t usually eat much during your rut and all.”
Katsuki cringes at the memory of his first scheduled rut when he basically raided the kitchen afterwards. “ Anyway, Aizawa asked me to keep an eye on you as always, just let me know if you need anything.”
A plate of still-warm pizza is pushed into Katsuki’s hands before Kirishima backs up, clearing his throat as he covers his nose, flushing slightly. “You may want to eat that quick, it smells like your rut is coming up fast.”
Katsuki just stands there up until Eijirou bids his farewell and heads back downstairs. Only then does he notice the quickly approaching, skin-searing feeling of his approaching rut. He does manage to get the pizza down, but almost as soon as he swallows the last bite, his fangs make themselves known, a clear sign to lock his door and batten down the hatches.
According to Recovery Girl, and the rest of the class, everyone else's ruts and heats have mellowed out in the recent year, partially due to the lack of stress now that the war was over and recovery efforts were well along the way. Only thing is, Katsuki’s HASN’T. If anything, the new constant schedule just made it easier to sequester himself in his room until it was over. No more accidentally ripping up the dorm couch because his body skipped the PRE-rut stage.
No, instead he gets to spend a day or two uncomfortable and more irritable only to then be hit by the proverbial truck of hormones and dazed thoughts for four days. Which he would normally not give a shit about. The icing on the cake is that any thoughts Katsuki DOES have revolve around a certain rock hard redhead.
THAT is the main problem.
Katsuki’s need for the Eijirou isn’t just a lighthearted crush anyway, and it grows into a full-blown obsession when he is in rut. He wants the fellow Alpha’s scent, wants to hear his voice, even begs for his knot at the peak of things. It’s embarrassing to say the least, and Katsuki is glad they put in the extra layer of soundproofing right around the time the class was presenting.
Because if not, the threat of the redhead hearing the absolute sin that comes out of Katsuki’s mouth during his rut would make the blond want to chug an entire bottle of soy sauce. Needless to say, Kirishima Eijirou has been a staple in Katsuki’s rut-hazed delusions since he presented.
Except that Alphas sharing a rut together is grounds for a hospital trip rivalling a small natural disaster. Between the rush of hormones and an Alpha’s natural possessiveness, it’s never recommended that an Alpha help another through rut. That doesn’t make him crave Kiri any less though.
In fact, the thought of Kirishima pinning Katsuki down, nipping at him to submit while he fills him with his cock only seems to make the Alpha all the more needy for his best friend. He’d actually caught himself staring at Kirishima’s teeth on more than one occasion during his pre-rut due to Kirishima almost always having his fangs out, a small side effect of his quirk.
The marks he wished those teeth would do to him.
But now is not the time to think about that. Katsuki is already riled up, and those thoughts are only going to make it worse. His hole clenches around nothing as the Alpha growls, rutting against the pillow. “Fuck, it’s this bad already?” Katsuki growls as he reaches into the drawer next to his bed, pulling out a fresh bottle of lube. Best to stretch himself now while he is still lucid.
Only a few fingers in has Katsuki biting down on his pillow, precum dripping from his cock even more as his body tries to figure out whether or not to fight it. C'mon dammit! We have to do this if we ever want that shitty-haired Alpha one day. The heat in his body flares as he imagines said Alpha stretching him with his thick fingers as his soft voice whispers into his ear.
Panting heavily, he scrambles to the edge of his bed, rifling underneath until his hands ghost against a smooth box. Pulling it out, he quickly rifles through it until he finds exactly what he was looking for.
A false Alpha knot.
It took ages for him to find one just right. Only the best for the best… right? Wasting no time, Katsuki lubes the toy up generously before teasing the tip at his entrance. As he pushes the toy deeper and deeper, he can’t stop the deep groan that rumbles from his core.
“Oh, fuck… I always forget how big this fucker is,” Katsuki grunts into the pillow. He lets himself adjust for only a moment before the frustration finally boils over. The next thing he knows, Katsuki is roughly fucking himself with the toy, the only sounds being his moans and the sweet squelching of the toy as it fucks some of the lube out of him.
A little too roughly, apparently, as one particular thrust hits that little spot, causing his other arm to give out from under him. The next thing he knows, he lands on his back on the ground, causing his grip on the toy to fall out from him and rolls under his bed. Just as he is reaching under to grab it, he hears the thump of his door being flown open. One look at the feet of the person that burst in has him swallowing a whimper.
He knew those dumbass red crocs anywhere.
“Katsuki? I heard something happen and came to check on you. Are you…. okay?”
A red blush runs all the way across the blond's body as he hurriedly tries to move out from under the bed, only to find the other Alpha was now standing right behind him.
When did he get there?!-
A large hand comes to rest on his hips, caressing him softly. “You sure? Sounded like you fell pretty hard. I could help you up.” Eijirou’s other hand comes to rest on Katsuki’s other hip and the blond Alpha lets out a warning growl. That seems to push Ei out of whatever fog he was in and he quickly backs away. “Right, Right. Sorry man, I’ll just… go.” Katsuki takes the chance to move out from under the bed, fallen toy in hand.
Eijirou’s eyes lock onto the toy and his face flushes. “Is that- an alpha dildo? I thought you- I didn’t-” Katsuki flushes and attempts to toss the toy at the other boy. “Get OUT.” The attempted growl only comes out at a weak whine as Eijirou’s eyes roam over him before flicking over to the toy as it lands next to him. “You can take all of this Kats…?” He asks breathlessly, the smirk that follows sending shivers up Katsuki’s spine.
“How many times do I have to say this, Shitty Hair… LEAVE…please.” The blond curses the slight tremble in his voice as Eijirou picks up the toy, eyes sparkling with… something. Walking over to him, Eijirou kneels down and holds the still lubed toy up. “Do you think you can show me?”
What?
Katsuki freezes, face laced with confusion. “Wha-? What the fuck are you talking about?!” Bright red, puppy-dog eyes stare him down as the redhead licks his lips. “Cmon Kat, I’ve always wondered how you’d look stuffed full with an alpha’s knot. And now that I know you can take it, I really wanna see.”
Later on, Katsuki would blame it on the rut-brain combined with the mixture of his and Kirishima’s scents clouding his judgement. But right now, Katsuki only saw this as getting what he’d been wanting for years. After taking a deep breath, he grabbed the dildo out of Eijirou’s hands and stood up, climbing back into his bed.
“Fucking- fine. Just don’t make this weird.”
Deep breath Katsuki. It’s not like our crush of a lifetime is currently in your room, watching you, while you are rutting.
He feels his Alpha growling low in his throat at the thought of another Alpha in his space, but it quickly turns into a low rumble of need as more of Kirishima’s heavy scent fills the room. Fuck he smells so good . He watches as Kirishima sits across from him, eyes drawing a heated trail up and down his body.
Leaning back on the bed, Katsuki wastes no time repositioning the dildo back at his entrance. As it slides deep inside he bites his lip to stifle the moan. Even with his eyes closed, the heat of Eijirou’s gaze spurs him onward, pushing and pushing until he feels the thick plastic knot kiss at his entrance.
A low growling sound echoes through the room suddenly, causing Katusuki to open his eyes only to see that the deep crimson in Eijirou’s eyes has been swallowed by the void of his pupils. When their eyes met, Katsuki whined at the obvious hunger in his best friend’s eyes.
“ Go on, Kats. Take it all.” Eijirou’s voice echoed in the blond’s ears. The tension in the air is thick with the smell of Katsuki’s rut, but also now with the added scent of Eijirou. It’s enough to make any omega’s eyes roll back into their skull, and the effect it had on Katsuki was hardly any better.
Forcing himself to relax a bit, the Alpha grinds the knot against his hole until finally, with a low moan, it slips inside. Almost immediately, Eijirou is on his feet, racing the other in two long strides as he growls appreciatively. One look at the large bulge in his sweats has Katsuki shaking as he is suddenly face-to-face with the redhead.
“Fuck Katsuki. That’s so hot.”
One of Eijirou's hands rests itself on Katsuki’s thigh, pulling a rumbling croon from deep within his chest. “Ei… please.” Katsuki begs. Taking that as encouragement, the redhead is quick to strip his pants and join the fellow alpha on the bed, quickly slotting himself between his thighs. “I’m right here Katsuki. What do you need?”
It seems the rut had finally fully set in as Katsuki’s crooning turns into a deep growl as his legs lock around Eijirou’s waist. “ If you don’t fuck me soon I might explode. So what are you waiting for, a fucking invitation?” The Alpha watches as Eijirou’s hands tighten their grip on his calves before using them to push his legs further apart as he smirks. “Well then, good thing I’m right here, all ready for you. Now if you don’t mind…”
Katsuki hardly has the chance to process what he had said before the toy is being pulled out slightly, only to be thrust deeper inside before being removed completely. Just as he is about to complain, he feels the push of a finger at his entrance. “Wha-?”
Eijirou chuckles deeply as he leans close to Katsuki’s ear. “What… you didn’t think that toy was the right size, did you? What’s the phrase? I’m a grower not a shower.” Katsuki’s eyes widened.
“ Like hell you are! There’s no way a monster like that can get any bigger.”
Any panic in Katsuki’s body is quick to fade as the finger immediately finds that special place inside of him. Causing him to let out a startled moan. Said finger continues to abuse this spot until Katsuki is shaking with pleasure, yet each time he feels himself on the cusp of release, Eijirou pulls out and adds another finger. By the time he has reached four fingers, Katsuki is close to begging.
Each time, in between adding more lube and another finger, Eijirou took his time, laying bite after bite along Katsuki’s body, wherever he could reach. The blond was so distracted by the fingers inside of him he hardly noticed.
Finally, as if sensing he was at his limit, Eijirou grinned and positioned himself at Katsuki’s entrance. “I hope you’re ready, Kats. Gods I’ve wanted this for so long you can't even imagine. “ More words flood from the redhead's mouth as he finally pushes inside, only drowned out by Katsuki’s moans. He can vaguely hear Eijirou’s words turn into grunts of pleasure as every nerve in his body seems to light on fire the deeper he pushes into him.
Once fully seated inside, Eijirou leans down to capture the blond’s lips in a searing kiss, not moving until he feels Katsuki’s body relax slightly. When he starts moving, the soft popping of Katsuki’s quirk reaches Eijirou’s ears, and the redhead distantly thanks Katsuki’s parents for buying him fire-proof bedding.
As Eijirou’s hips finally pick up speed, Katsuki has to fight his instincts to not immediately cum. “H-holy shit, Ei.” and “Oh, fuck.” seem to be the only words he remembers as he starts losing himself in the pleasure.
When he is finally on the very edge, he begs and begs for something, anything. Eijirou, knowing exactly what he needed, leans close enough for Katsuki’s breath to brush against his shoulder as he whispers into his ear.
“It’s okay Katsuki. Take a bite. I got ya.”
Like a long held chain finally breaking, Katsuki does as he’s told, biting down as he sees white and finally cums hard in between their bodies. Before he passes out, he hears Eijirou curse softly under his breath as he keeps going before he feels the other Alpha pull out as he cums too, his own release joining Katsuki’s in a pool on his stomach.
Then everything fades to black as the exhaustion catches up.
The first thing he notices as he wakes back up is the lack of the normal pain or need that accompanies his rut. Sitting up and rubbing his eyes, he is shocked when he catches sight of red hair laying next to him. Eijirou props himself up on his arm and smirks knowingly.
“So… how ya feeling blasty?”
The redhead laughs as his best friend blushes deeply before a pillow is smashed into his face. “Shut up.” As Eijirou continues losing his shit next to him, Katsuki relaxes back on his bed, trying not to let Eijirou catch his smile.
After his rut is over, they’ll probably have a long, long talk. But for now, Katsuki supposes his ruts aren’t all that bad.