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Kirishima hums as he watches Katsuki dodge another kick coming in from Izuku, barely leaping out of range at the last second. They’re sparring, strict hand-to-hand with no quirks like they do every Saturday, which means they’re pretty evenly matched.
It’s exciting, because these matches really could go either way, and usually it ends up being a best 2 out of 3 deal (sometimes pushed to 3 out of 5 if one of them isn’t in the mood to lose). Truthfully, he and Todoroki, who’s planted on the bleacher beside him, could be stretching in preparation for their turn coming up next, but watching Katsuki and Izuku spar is truly an event. Besides, he’d never pass up the chance to watch a riled up, sweaty Katsuki.
Katsuki takes an elbow to the side, and falters a bit. Kirishima’s seen him take a hit of course, but the best part is always the look of determination that crosses his face afterwards. Kirishima watches as he lets out a snarl and hits Izuku with a lightning fast one-two punch. The energy between them is so high that Kirishima can practically feel it in the air, crackling between them. Kirishima’s trying to process why that look Katsuki has on his face seems so familiar when the cogs start turning in his brain.
Katsuki knees Izuku in the gut, knocking the wind out of him just enough to get him to the ground in a pin. Katsuki lets out a yell of victory as a feral smile graces his face, and…
Kirishima knows where he’s seen something similar before.
“Hey Roki,” Kirishima says, eyes still jumping over where Katsuki and Izuku are both panting, sweating, Izuku’s wrists locked beneath Katsuki’s fingers. “Do you think they ever…?”
Kirishima feels Todoroki looking over at him, waiting on him to continue, but his eyes are glued to the pair on the field.
“You know,” Kirishima finally tears his eyes away from Izuku and Katsuki.
He waits for Todoroki to fill in the blanks, but he just looks silently back at Kirishima.
“Hooked up?”
“Oh,” Todoroki says before turning back to watch them start the next match. “They haven’t. Izuku would’ve told me.”
Kirishima hums for a second. “Not even back in school when….” He doesn’t have to elaborate this time, he knows Todoroki knows. Knows he means that day back in the rain in their first year.
Todoroki shakes his head. “Izuku hasn’t told me everything about…” he pauses for a second, “what they went through those few months after everything. I know they got closer but…” He looks like he thinks about it, eyebrows furrowed. He gives a little shake of his head again. “When we got together Izuku was very honest about who he was with in that way and Katsuki wasn’t on that list.”
Kirishima is quiet, thinking. He and Katsuki had talked about it too, when he got his head out of his ass and finally admitted he wanted to be with Kirishima romantically. Despite receiving confessions all throughout high school, Katsuki’s roster—besides Kirishima—was surprisingly empty. He supposed Katsuki would’ve mentioned if Izuku was on said roster, but.
His eyes catch again on the way Katsuki is looking at Izuku. This time he’s ended up under Izuku and Kirishima realizes it’s not just Katsuki who looks at Izuku that way, it’s the other way around too.
“So you’re telling me,” he says,”that tension,” he glances over his shoulder and jabs his thumb at the couple still wrestling, “is just bros being bros?”
Kirishima is a little surprised at Todoroki’s snort. “Oh no, I definitely agree there’s something there.” He presses his lips together, thinking about his next words. “I’m just not sure they even realize it.”
He raises his eyebrows at Todoroki. He supposes it’s possible Katsuki doesn’t even realize the way he looks at Izuku. Despite his abrasiveness, when Katsuki’s in something, he’s all in, and that includes his romantic relationships. He’d never do anything to hurt Kirishima, not intentionally anyway, but is it possible that this…whatever…with Izuku is so intrinsic that Katsuki doesn’t even know enough to bring it up with Kirishima?
While he was stuck in thought, he didn’t realize Todoroki was doing the same until he breaks the silence. “Don’t,” he says, voice quiet, pausing for a second then continuing, “don’t hold it against him, okay? Katsuki and Izuku are…” he stops, face drawn up in pensiveness as he looks out at them, “they’re just Katsuki and Izuku.”
He lets Todoroki’s words sink in for a moment before the lightbulb goes off and he realizes Todoroki’s trying to placate him because he thinks Kirishima might be jealous. Is he jealous? Kirishima hums, watching Katsuki go after Izuku punch after punch, relentless, wild smile lighting up his face and Izuku meeting him back hit for hit and Kirishima realizes, oh. Oh. No, that’s not jealousy he’s feeling.
“I’m not upset,” Kirishima starts. Todoroki starts to respond with relief when Kirishima barrels over him. “I may think it’s kinda hot.”
Todoroki’s head spins like it’s on a swivel, wide eyes landing on Kirishima.
Kirishima meets his gaze. He’s never thought about this before, this thought of…sharing Katsuki. And he knows it’s risky, saying anything to Todoroki at all, because that’s his partner out there too, caught in a tangle of tension with Katsuki that’s almost definitely probably certainly not strictly platonic. Todoroki could stomp away, swear at him, hell a punch wouldn’t be uncalled for with what Kirishima’s insinuating.
But Kirishima’s been friends with Todoroki for years by this point, one of his closest friends. He knows when Todoroki’s upset.
He’s not mad about it.
“C’mon bro,” Kirishima whispers, and Todoroki can’t help but wrinkle his nose and laugh a little. “You can’t tell me it wouldn’t—them together—wouldn’t be the hottest thing to ever happen.”
He looks back out at the two of them, and somehow they’re locked in some kind of wrestling hold that doesn’t really look like wrestling. Kirishima can practically feel Todoroki ruminating. Izuku pins Katsuki again, chest heaving and smiling down at Katsuki. He watches Izuku lean down slowly, eyes intense and a lump lodges in Kirishima’s throat because surely they’re not—no. Izuku whispers quietly into the space between them, words low and intimate.
Kirishima swallows. He didn’t think they were…but it definitely looked like.… He catches Todoroki biting his lip in what Kirishima is sure he thinks is subtlety.
“Dude,” Kirishima gestures at the two still out on the field, as if to say are you seeing this?
“Well,” Todoroki huffs under his breath, “you’re not wrong.”
🔀
Kirishima’s kinda surprised how quickly things move after that. He brings it up with Katsuki one morning when they both get to sleep in and relax a bit.
“Have you ever thought about Izuku?” Kirishima asks, hand lazily splayed over Katsuki’s hip under the covers.
Katsuki’s voice is rough with sleep, his eyes barely open for the morning. Katsuki’s sleepy face makes warmth swell in Kirishima’s chest. “Damn nerd plagues my thoughts every day, what about him?”
Deep down Kirishima knows there’s probably a better way to ask, but Katsuki would probably appreciate getting straight to the point. “Have you thought about having sex with him?”
A strangled noise escapes him and he stares at Kirishima with wide eyes.
But it’s not a no.
“Explain.” Katsuki demands.
“So…” Kirishima starts, “Yesterday, when you guys were training, I was talking to Todoroki and….”
🔀
A sleepover is what they land on. It’s supposed to be low pressure, fun, casual. Katsuki will make dinner and Izuku and Todoroki will bring wine and dessert, they’ll watch a movie together and whatever happens, happens.
That doesn’t mean Kirishima isn’t a nervous wreck when he hears a knock on the door that evening. He freezes where he was getting out plates and silverware, turning to Katsuki with wide eyes.
“They’re here.”
“Well, open the door,” Katsuki says, still stirring the veggies he’s sauteeing over at the stove.
“But then they’ll come in,” Kirishima says, voice strangled.
Katsuki whirls on him like he’s grown two heads. “What the fuck, shitty hair? Why are you panicking?”
Kirishima doesn’t say anything. Katsuki moves the pan to the back burner so the veggies don’t burn, before crossing the kitchen to his husband.
“Hey,” he says, gripping Kirishima’s hands in his. “You know we don’t have to do anything if you don’t want, right? This is just dinner and a sleepover, remember?”
Kirishima heaves a breath before he looks Katsuki in the eyes, “I know, but I really like them, and you really like them, and I just want this to go well.”
“It will,” Katsuki reassures, “this is no pressure, right? If something happens then it happens, but if it doesn’t it’s just another night in with friends.”
Kirishima nods and takes a deep breath. He glances over to the tablet they have connected to their security system. He sees what he guesses is a very similar conversation happening on their front porch, with Todoroki gripping Izuku’s hands. He runs his fingers over Izuku’s knuckles and Izuku nods, but Kirishima can tell just from the way he’s standing that he’s a little nervous. Glad he’s not the only one.
🔀
A light snore draws their attention to the other end of the sectional. Kirishima smiles at Todoroki’s snort, gesturing to where Bakugou is splayed out on Izuku’s chest, sound asleep. “Still early to bed for him, huh?” Todoroki whispers.
Kirishima glances at the clock above their television. “9:45 is at least an hour past his bedtime,” he chuckles. His eyes follow the scarred hand that settles at the small of Bakugou’s back, seemingly moving on instinct because Izuku is asleep as well, head full of wild curls tossed over the arm of the chair. Watching them together makes Kirishima’s stomach do a weird, funny floppy thing, and makes him feel warm and fuzzy.
“I see Izuku is still a lightweight as well,” he nods to where Izuku had downed his own glass of wine before finishing off Katsuki’s. “We should probably get to bed, hmm?” Todoroki nods beside him before gently getting to his feet.
“Katsuki is a terror to wake up,” Todoroki says, padding quietly to look over the both of them. Kirishima can tell Todoroki’s stomach is doing that same floppy thing that his was doing earlier. “I’ll wake these two up if you want to, ah, get the bed ready.”
The bed. The bed where they’ll all be sleeping together. Kirishima nods, trotting down the hall. He gets lost in thought as he takes the heavy duvet off, knowing with the four of them together it may get toasty. As he grabs the lighter comforter, he thinks of his night. It was a lovely dinner, and he always loves getting to spend time with Izuku and Todoroki. Putting everything together in his mind he realizes…tonight was a date, wasn’t it? He went on a date with his husband and best friends, and it was lovely. The butterflies in his stomach makes him do a happy little wiggle, giggling to himself. He hasn’t had a first date since high school, and this couldn’t have been a better beginning to…whatever it turns out to be between them. Yeah they discussed that they wanted to fool around together, and it’s out in the open that there’s definitely some kind of feelings involved, but they had also all agreed to just…not overthink it and play it by ear.
As a pouty Katsuki and a drowsy Izuku make their way into the room, followed by a soft looking Todoroki, Kirishima can only hope that they want to do this again. Kirishima jumps into bed, scooching all the way back against the wall. He reaches for Todoroki, and from there it’s like a chain reaction, Todoroki grabbing for Izuku and Izuku pulling Katsuki in after them all.
They settle in, Kirishima shuts the lights with the smart switch, and it seems like almost immediately Katsuki and Izuku are back to snoring. Todoroki hums quietly as he snuggles down into the covers.
“You comfy,” Kirishima whispers. Todoroki sighs, humming in the affirmative, and when he opens his eyes Kirishima is struck by how gentle he looks.
“Hey Roki,” Kirishima says into the darkness between them. ”Um,” he should’ve thought about what he was going to say before starting but his mouth is already open now so might as well say what he really feels. “I’m glad we decided to do this.”
Todoroki does that smiles that he does, the little one that means he’s really, really pleased. Before Kirishima can say anything else, Todoroki leans forward and slots his lips against his. A shiver runs down Kirishima’s spine as he leans further into Todoroki’s space. He tastes minty from where he’d brushed his teeth before bed and a little spicy like the food Katsuki had made for dinner and good. He tastes good and like Kirishima wants to keep doing this forever.
Alas, Todoroki pulls back eventually, places another quick kiss on his lips and whispers, “Goodnight, Eijirou.”
Kirishima feels him groping around a bit under the covers but then there’s a cold hand tangling fingers into his own and Kirishima sighs, so elated. “Goodnight, Shouto.”
🔀
It’s late, easily the middle of the night, when he hears it. A sound pulls Kirishima lurching back to the land of the waking. He breathes deeply, feels the hand still in his and squeezes, and tries to make sense of what’s woken him up.
“Shut up, Deku,” a whisper into the night air, and that gruff voice is Katsuki’s for sure, but then—
A wobbly, stuttery moan floats around them, sounding like it was never supposed to escape. At the same time Kirishima realizes the bed is moving subtly, shaking rhythmically and oh, fuck. His eyes shoot open and he can’t make out what exactly he’s looking at until he pieces together where Bakugou’s head is.
It’s under the covers, bobbing slowly right where Kirishima would imagine Izuku’s cock is.
The heat that washes over him is overwhelming, knocking the breath from his lungs. Oh fuck, oh shit, are they—
He watches the silhouette of Izuku throw his head back, gripping the sheets below him, watches his chest rise and fall as he pants quietly through his nose.
They definitely are.
Kirishima gets so hard so quickly he gets dizzy. He feels a little bad for Izuku, he’s been on the receiving end of that wicked tongue and it’s hard to be quiet under normal circumstances, but this is on a different level.
Just then Izuku lurches forward, hands hovering awkwardly around Katsuki’s blanket-covered head. His voice is barely restrained, so obvious that Kirishima wonders how Todoroki is still asleep. “Kacchan—Kacchan—I’m—”
Katsuki pops off with a wet slurp. “Don’t you dare, shitty nerd, not until I can get that fuckin’ monster inside me.” Kirishima hears him muttering about how Izuku even walks with that third leg. He watches with wide eyes, barely moving and gripping a sleeping Todoroki so hard, as Katsuki climbs over Izuku’s hips and slides down in one smooth motion.
Twin moans rent the air, not restrained at all, and Kirishima’s silently thankful they’re so loud because the way he groans at the sight is loud enough for him to be discovered. Finally, Todoroki’s eyes peek open, his face still so sleepy. Kirishima wants to coo at him until Todoroki’s hand lands directly on where Kirishima’s tenting the covers.
“Eijirou?” he says quietly, voice soft with sleep. A shaky “fuck, there, yes—” in Katsuki’s rough voice draws his attention and he looks over his shoulder. “Oh.”
“Bout time ya woke up, Halfie,” Katsuki moans, a manic grin on his face as he leans over Izuku and slams his ass down. “Ei’s been creeping on us for like the last ten minutes.”
A hot flood of shame washes through Kirishima, but deep down he knows that Katsuki probably planned for this to go exactly this way.
Watching Katsuki writhe on top of Izuku is a thing of beauty; Kirishima knows from experience that Katsuki does this thing where he clenches on his way up that drives him crazy, and judging from the way Izuku’s barely holding on, it seems like he likes it too.
The slick sound of their bodies meeting, the bed shaking with them right beside them, everything is so erotic that Kirishima has to slam his eyes shut and muffle his moan in Todoroki’s hair when Todoroki reaches forward and grips his cock over his pajama pants.
“Fuck, please,” he whimpers, and that’s all the permission Todoroki needs to climb on top of him, pulling him out of his pajama pants and gripping them together.
Todoroki takes in a shaky inhale, thrusting against Kirishima’s cock and letting out a moan simultaneously.
Kirishima feels like he can’t control his hips, chasing Todoroki’s touch and taking in the sight beside him. He moans when Katsuki turns to him and says, “His cock feels so fucking good, Ei.” Todoroki pushes an unhinged groan into his neck, feeling overcome at the sight.
“C’mon, harder Deku, I know you can do it, fuck me harder,” Katsuki pants. Just then Izuku grips Katsuki’s hips hard and holds him aloft, green lightning sparking over his skin. He sobs, looking like he’s torn between staring up into Katsuki’s eyes and closing them to keep them from rolling back. “Kacchan, please, feel so good—Shou—Eij—” he stumbles over his words as he slams up into Katsuki so hard he bounces and throws a hand up on the headboard. Izuku’s tears soak into the pillow below him.
Just then Todoroki tightens his hold on Kirishima, trembling, “He always does that, you know? Cries when he starts feeling good.”
“Oh fuck,” Kirishima throws his head back for a second before pulling Todoroki into a filthy, wet kiss as he gets closer to tumbling over the edge.
“Gonna come, don’t fuckin’ stop Deku,” Katsuki says, jerking himself off furiously as Izuku pumps below him. Katsuki throws his head back and lets out a shout as he comes everywhere, white pools landing over Izuku’s chest.
Kirishima’s fingers dig into Todoroki’s side where he’s got his arms looped around his lower back, and he hears Izuku’s wobbly, wet cry as he comes right after Katsuki. “Fuck, Roki—” he’s cut off as the pleasure overwhelms him, tossing him into a deep abyss of euphoria as he feels Todoroki cry out above him and still.
The only sound for the next few minutes is panting. Kirishima gingerly uncurls his toes and tries to feel his face again. Fuck, that was the hottest thing he’s ever done.
“Fuck,” Katsuki groans as if he can read Kirishima’s mind. He slumps on top of Izuku, mirroring Kirishima and Todoroki. Katsuki nuzzles his forehead into Izuku’s neck, and then throws his hand out into the space between them. On instinct Kirishima reaches out as well, tangling their fingers together.
A different kind of warm washes through him as Izuku’s hand lands on top of his, and then Todoroki’s follows it. A giddiness rises in him, full and satisfied and happy, and he can’t help but smile at how content he is.
They sit in silence a bit longer before Katsuki sits up, slapping Izuku’s chest.
“Don’t get comfortable, we all have to shower.”
Kirishima whines at the thought of moving, and then snickers when he realizes Izuku’s whining as well.
Katsuki wrinkles his nose, “There’s sweat and jizz everywhere, you nasty asses, get up.”
Izuku blinks slowly at Katsuki, “What if I volunteer to sleep in the wet spot?”
Katsuki’s expression drops, “That is disgusting, Deku.”
“What if I volunteer to blow you in the morning, and Izuku volunteers to sleep in the wet spot?” Todoroki says quietly, voice rough and recovering from the intensity of earlier.
Katsuki squints as if he’s deciding, but Kirishima knows Katsuki’s mind was made up as soon as a blowjob from Todoroki was on the table.
“You drive a hard bargain, Half-n-Half…but deal.”
Kirishima chuckles and closes his eyes, running his hand down Todoroki’s spine. He grips Katsuki’s hand then Izuku’s in turn.
He couldn’t be more excited to see what beautiful development comes next.