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The second event of the sports festival has just ended when Izuku's classroom door is flung open and shut. There's no lock on it, but no one is in this part of the school right now.
At least, they shouldn't be.
Katsuki is pushed into the room and towards the desk. Izuku has still kept up with physical training even after the ember had faded, so he's strong and solid as he pushes Katsuki around. It's pretty hot.
Katsuki grabs him by the tie and hauls him forward into a bruising kiss. They don't have a lot of time; Izuku doesn't want to miss his students, and Katsuki is technically on patrol. But there's long enough to sneak away and fool around.
Katsuki is pushed onto the desk, and he wraps his legs around Izuku's waist as Izuku’s tongue delves into his mouth. He hums into the kiss, a big scarred hand tracing up Katsuki's back as they fall into each other. It’s been a while since their schedules had lined up, a while since they’d been able to be together. Katsuki has been working as much overtime as he possibly could to pay for Izuku’s secret suit, so most nights the only thing he has the energy for is crawling into bed beside Izuku and falling immediately to sleep. It’s why they’re taking such a risk and doing this here.
That and because it’s hot. Sneaking away to fuck like they were teenagers again. That and Izuku’s suit. Katsuki has a Thing for Izuku’s suit, how nicely it contours to his body, how strong he looks in it. Anytime Izuku got dressed up, all Katsuki could focus on was how much he wanted to undress him.
They don’t, unfortunately, have time for that. Katsuki wishes they could take their time, wishes he could feel and kiss up Izuku’s body, wishes he could do all the things they haven’t been able to do in weeks. But unfortunately all he gets is this; a forbidden tryst among the biggest festival in the country, while everybody’s eyes are elsewhere.
Katsuki hops off the desk, shoots Izuku a crooked grin, and then drops to his knees.
“Hng, Kacchan,” Izuku says, running a hand through his hair. “We don’t really have time.”
“Don’t care,” Katsuki says, already pulling at Izuku’s belt. “I want to suck your dick.”
“No objections,” Izuku says cheekily, cupping Katsuki’s face with his hand as he works on getting his cock out of his pants. He’s half-hard, a fact Katsuki plans to rectify immediately, leaning in and nosing at his cock. He licks up the side before he sinks down on it, taking it in his mouth and down his throat, tongue working at the underside, feeling it firm up to full hardness in his mouth. Izuku lets out a shaky sigh and cards his fingers through Katsuki’s hair, shuffling them around so Izuku is back against the desk and Katsuki is on his knees in front of him. He continues to bob his head, taking Izuku’s cock deep and then back again, setting a steady rhythm that Izuku helps with miniscule thrusts into his mouth. It’s never too much; part of Katsuki wishes Izuku would just fuck his face, but another part of him wants to be in control, and another part of him wants to just skip to when he gets fucked over Izuku’s desk.
“Oh, shit, Kacchan,” Izuku says shakily, one hand gripping the corner of his desk and the other gripping Katsuki’s hair. “God, your mouth—”
Katuski hums at the praise, pleasure spiking through him. He’s hard in his uniform, and he resists the urge to touch himself, wanting to focus completely on Izuku. He brings a hand up to fondle Izuku’s balls, teasing them with his nails and causing Izuku to let out a shaky breath, a stutter of Katsuki’s name. He takes Izuku deep again and holds him in his throat, breathing through his nose as Izuku continues to shallowly thrust his hips.
“Mm, Kacchan,” he says, pulling slightly at Katsuki’s hair. “C’mon, I don’t wanna come.”
Satisfaction blooms inside him at the knowledge that Izuku is close already. He pulls off and jerks his cock a few times with his hand, grinning up at him.
“Gonna come already, Sensei?”
Izuku groans again, eyes fluttering closed. “Kacchan,” he says, swaying slightly on his feet. “You know that’s not fair.”
Katsuki chuckles and leans forward to inhale at the crease of Izuku’s thigh. “Pervert,” he says fondly.
“Get up here,” Izuku says, tugging at Katsuki’s hair, and Katsuki listens, hopping up and pulling Izuku in for a deep kiss before he reaches into one of his pockets and pulls out the packet of lube.
“Hurry up,” he orders. Izuku gives him a look.
“You were the one who wanted to blow me.”
“Yeah, and now I’m telling you to hurry up.”
Izuku grumbles and switches their positions around again. He bends Katsuki over the desk and yanks his pants down to his ankles, kicking his feet apart as best he can before he runs his hands over the swell of Katsuki’s ass, spreading his cheeks. He runs a finger over his hole and Katsuki shivers, handing the lube back to him.
Izuku takes it, tearing into it and pouring some over his fingers before he brings them to Katsuki’s hole. He starts with one, long and thick inside of him, and Katsuki rolls his hips back.
“I told you to hurry up,” he says, and Izuku makes a noise before he slips another one inside. There’s a stretch; it’s been a while since they’ve been together, and Izuku’s fingers are big.
“So impatient, Kacchan.”
“Maybe I just don’t want us to get walked in on,” he argues back. He’s not that concerned about it, actually—he just really wants Izuku inside him.
Izuku’s fingers fuck into him, and Katsuki grips the edges of the desk. The position has him feeling vulnerable, bent over and spread open, and that edge of vulnerability just increases the heat inside him.
Izuku fucks him hard and fast with his fingers, getting him ready for him, muttering praise into Katsuki’s ear as he drapes his body over his back. Katsuki lets his forehead drop to the cool desk, rocking his hips back to roll onto Izuku’s fingers. He adds another, the stretch feeling absolutely delicious after so long, the stretch and the intimacy that comes from it. He missed having Izuku this close, missed him like a lost limb.
“C’mon,” he says. “C’mon, Sensei, fuck me.”
Another strangled moan from Izuku, who was really so predictable. The first time Katsuki had brought that out during sex, shortly after Izuku had landed his position at U.A, Izuku had come on the spot.
Izuku yanks his fingers out of Katsuki’s ass. Katsuki can’t see what he does next, but he knows Izuku well enough to picture it. The way he’ll be biting his lip, the way he spreads the rest of the lube along his dick, the way he stares down at Katsuki’s ass hungrily. Katsuki arches his back a little more, showing off his ass, and is rewarded with Izuku’s big hands pulling his cheeks apart to better access his hole. He brings his cock to Katsuki’s ass and pushes in with just the head, fucking Katsuki shallowly.
“We don’t have time for this,” Katsuki says through gritted teeth, repeatedly stretching over the head of Izuku’s cock. “Fuck me properly.”
“I can’t help it,” Izuku says. “I miss you, Kacchan.”
Guilt nips at Katsuki’s heels. Izuku doesn’t know what Katsuki is doing, what they’re all doing. He doesn’t know why Katsuki is taking so much overtime, why he’s so frugal, why he’s so secretive sometimes. But it will all be worth it when the suit is complete, when Izuku is by his side again.
“I miss you, too,” he says. “That’s why I want you to hurry up and fuck me.”
Izuku pushes in deeper, and Katsuki groans at the feeling. He grips the edges of the desk even harder, knuckles going white as Izuku pushes all the way inside him, finally bottoming out with his hips pressed tight against Katsuki’s ass. He gives Katsuki a moment to adjust, a soothing hand tracing down his back before landing on his hips. Katsuki takes a deep breath and then wiggles his hips. He doesn’t say anything, but he doesn’t need to. Izuku knows him.
Izuku pulls out almost all the way before he slides in again at a slow pace. Katsuki groans, fucking his hips back at the exact moment Izuku bottoms out so he manages to get even deeper, and they both moan at the feeling. Izuku keeps that up, that slow and steady and deep pace, and Katsuki’s legs are starting to wobble where they’re holding him up over the desk.
“Harder,” he finally orders. “C’mon, Sensei, fuck me harder.”
“God,” Izuku says, but he listens, speeding up his thrusts. Katsuki moans in appreciation of the newfound speed, as Izuku fucks into him and fucks into him. His hands are vicelike on Katsuki’s hips as he’s dragged back repeatedly onto Izuku’s cock. His own dick is hard and trapped against the desk, rubbing slightly painfully against it, but he ignores it in favour of hanging on to the edge of the desk, keeping himself steady as Izuku thrusts into him. The desk scrapes across the ground in a sound that leaves little to the imagination, and Katsuki hopes that there’s no one passing by that can hear.
“Shit,” Katsuki swears, as Izuku’s cock hits him in all the right places. He closes his eyes and tries to picture what Izuku will look like, still in his suit, pants shoved down to his thighs, head thrown back and eyes closed as he loses himself in Katsuki’s hole. He can see it clearly in his mind’s eye, just as he can see himself, bent over the desk while he fucks his ass back on Izuku. An entirely damning picture, but hot. Pro hero Dynamight getting fucked within an inch of his life.
“Kacchan,” Izuku says desperately, voice high-pitched and breathy. “M’close.”
Katsuki lifts his head so Izuku can better hear him. “That’s it,” he says, knowing Izuku will make it up to him even if he comes first. “Gonna fill me up?”
“Kacchan,” Izuku gasps, hips stuttering. “Oh, Kacchan—”
Izuku always does the same thing when he comes; he throws his head back and fucks in as deeply as he can, spilling inside of Kacchan before he starts to shallowly thrust his hips, pushing his cum deeper inside.
He jerks his hips a little bit more, letting out a long, pleased noise as he comes down from his high. He loosens his grip on Katsuki’s hips before he pulls out slowly.
“Kacchan,” he says. “Stand up and turn around, please.”
Katsuki listens gladly. His knees creak slightly as he straightens, shaky from being bent over the desk. He turns around so he’s facing Izuku, cock still hard between them.
Izuku, much like Katsuki had earlier, drops to his knees. He takes Katsuki’s cock in his mouth and sinks down eagerly, hand jerking off the base of Katsuki’s cock as he swirls his tongue around the tip. Katsuki pets a hand through Izuku’s hair.
“That’s it, Sensei,” he says. “Take my fucking cock.”
Izuku looks up at Katsuki and goes limp in his hold; Katsuki grips his hair and starts to fuck his face.
He doesn’t last long, wound up from the sex. He fucks into Izuku’s wet mouth and warm throat, chasing his release, and when he finds it he pulls out just enough that he can come inside of Izuku’s mouth. Izuku moans as Katsuki unloads, swallowing dutifully everything Katsuki gives him.
When he’s finished he pulls back and looks down at Izuku, chest heaving. Izuku smiles up at him before he opens his mouth, showing he swallowed everything Katsuki had given him. Katsuki grins down at him.
“Good,” he says, before he helps him up. Izuku leans in to kiss Katsuki before he tucks himself back into his pants; Katsuki does the same.
When they’re back to looking professional, Izuku smiles sadly at him.
“What time will you be home tonight?” he asks.
Guilt licks up his spine as he says, “Not until late.”
Izuku’s smile doesn’t falter; he’s used to it. “Okay,” he says. “I’ll see you later, then.”
He leans in to kiss Izuku deeply, trying to memorize the shape of his mouth and the taste of his lips.
“I’ll get home as soon as I can,” he promises, and Izuku smiles at him again before he turns to leave. Katsuki will wait and stagger their exit.
He sighs and sags against the desk. Soon; soon all of this will be worth it. Soon Izuku will be beside him again.
With that thought spurring him on, Katsuki goes back to work.