#dkbk #nsfw

tl;dr: deku has a kink for katsuki thanking him

— “Fuck *off*, Deku,” Katsuki practically snarls, ripping his arm out of Izuku’s grip, “I didn’t ask for your help!”

He storms off and Izuku just watches him go, running a gloved hand through his wildly curling

hair, still windswept from the earlier fight. It’s not that he expects a “thank you”—he didn’t become a hero for the praise—but, still, it would be *nice* if Kacchan would at least acknowledge the fact that Izuku saved his life, again.

Shaking his head, Izuku turns back to the

citizens they’d just saved, but they’re already being given shock blankets and ushered towards the back of an ambulance by a handful of other heroes. He heads in the direction Katsuki took off instead.

The adrenaline is wearing off fast, leaving Izuku with the sort of bone-deep

tired that means he’ll be sleeping at least ten hours straight. Internships have been absolute hell this semester. And worse, he and Kacchan ended up at the same agency again, this time without Todoroki as a buffer.

To say it’s tense is the understatement of the year.

When Izuku makes it back to the dorms he immediately flops down on his bed, too tired to even shower. Today had been particularly grueling. Kacchan was absolutely reckless during the rescue, worked up that Izuku has apparently been “hogging the spotlight for weeks”.

And then Kacchan went and nearly got himself captured by the villain, as if Izuku’s heart could take it.

He was honestly surprised he hadn’t passed out from the sheer amount of adrenaline pumping through him as he’d snatched Katsuki back,

pulling the other behind himself instinctively. That particular gesture had gotten Izuku an earful later on. He groaned into his pillow just thinking about it.

Had no one ever taught Kacchan to just say thank you?

Izuku stares at the ceiling aimlessly. He’s known Kacchan practically their whole lives and he still can’t think of a single time he’d thanked someone. Sure, he’d shown his gratitude in other ways, but saying the words would be as good as admitting he’d needed help,

and that was one thing Kacchan would never do.

Maybe that’s why Izuku can’t stop thinking about it, mind turning in circles as it tries to conjure up scenarios of how it’d happen, each more unlikely than the last.

What expression would Katsuki make when he said those two little words? Would he blush, humiliated at having to stoop so low as to thank *Deku* for saving his life?

Izuku licks his lips at the thought, shifting slightly on his bed. But no, that doesn’t seem like Kacchan.

The scene changes in his mind’s eye: this time Katsuki swaggers up to Izuku with the same effortless confidence he’s had since they were kids. He takes one look at Izuku with those sharp red eyes and knows exactly what he wants;

Izuku has never been good at keeping secrets, especially from Kacchan.

“Don’t tell me you’re waiting for me to thank you, nerd,” Imaginary Kacchan scoffs. They’re in a deserted hallway in the dorms, and it takes no effort at all for Katsuki to shove Izuku back into a wall and

corner him like prey. Katsuki leans in close until Izuku can feel the tickle of his breath against his cheek, smell the sweet tang of Katsuki’s sweat. His lips are curled in that victorious smirk, the one that always makes Izuku want to punch him and praise him all at once.

He can feel their chests brushing with every one of his ragged inhales as Katsuki whispers, “You know I’d never do that.”

Izuku opens his eyes, not sure when he’d closed them, and is horrified to find he’s hard. But it’s not because of Kacchan. Of course not.

It’s just been a while, that’s all.

Shifting around to get more comfortable, Izuku palms himself lazily through his pants and lets his mind wander again.

Of course Kacchan wouldn’t make it easy, even in the privacy of his own mind. Did Izuku really expect Katsuki to seek him

out so they could have a heart to heart? That’d only happened once and the result had been extensive property damage and a couple days suspension. So no, it’d definitely take more force to get Katsuki to show some gratitude. Real gratitude at least.

It’s easy enough to picture Kacchan teasing him.

“Fucking pervert,” he’d laugh, glancing down between their bodies at Izuku’s cock, shamefully hard in his uniform slacks. He’d be at Katsuki’s mercy, wedged between the wall and the hard press of his body.

“You really want to hear me say it, huh?” Imaginary Kacchan asks, and Izuku’s cock throbs a little. Fuck, he kind of does want to hear Kacchan say it. And not just to anyone–he wants Katsuki to say it to *him*. How many times has he saved Kacchan’s life?

He’s risked everything for him, and it’s not like he’s asking for much. He just wants Katsuki to thank him and *mean it*. Doesn’t he deserve that?

“How do you want me to thank you, Deku?” Imaginary Katsuki asks, dragging his hand down Izuku’s torso, palm hot through the fabric

of his shirt. He keeps going, down down down, until he reaches Izuku’s belt, then he leans back and stares Izuku in the eyes, lips still fixed in a smirk.

Izuku shoves his hand down his pants, letting out a groan of relief when he finally wraps it around his cock.

There’s no denying it anymore. He’s jerking off to Kacchan, but not even the guilt of picturing his childhood friend like this is enough to stop him.

“Do you want me to tell you how grateful I am, Deku?” Katsuki asks but it’s not enough. He pants, eyes shut tight, no longer

fighting the sinful pull of his imagination. In his mind, Katsuki slowly sinks to his knees. “Or do you want me to *show* you?”

Even in his mind Izuku can’t keep his composure. His voice comes out in a rasp as he looks down at Katsuki and says, “Show me.”

And Kacchan does, undoing Izuku’s belt until it falls to the floor with a dull *thunk*. He peels Izuku’s pants and boxers down to his knees, and lets out a breathy little moan at Izuku’s dick in his face. He doesn’t hesitate, licking up the underside before taking the head into

his mouth, holding Izuku’s gaze the entire time and looking so cock hungry that it takes everything in him not to cum then and there.

“Fuck,” Katsuki says as he pulls off with a wet ‘pop’. The sound makes Izuku’s toes curl in his sneakers, “you’re big.”

Izuku can’t help but moan. Kacchan’s mouth is shameless. Katsuki grins up at him mockingly, rough hand working his dick, squeezing just the way Izuku likes. “Big cock for a big shot hero, huh, Deku?”

It’s a line straight out of a bad porno, and it gets Izuku so hot he almost

can’t stand it, legs trembling as he reaches down and buries a hand in Katsuki’s hair to steady himself. The real Kacchan would probably blow him up for that, but this imaginary Kacchan doesn’t seem to mind. In fact he leans into the touch like a cat, mocking grin softening into

something approaching a genuine smile as he stares up into Izuku’s eyes. He looks so *grateful* to be on his knees playing with Izuku’s cock.

“You’re my hero, Deku.”

And just like that Izuku cums, harder than he has in months, all over Katsuki’s face.

When Izuku wakes up he’s a mess. His hand is still down his pants and covered in dried cum, and he smells disgusting. He rolls out of bed and trudges toward the bathroom, discarding clothes as he goes.

By the time he’s showered and dressed in his uniform,

he’s running late. He laces up his red shoes, swings his backpack over his shoulder, and runs to class.

As he bursts into the classroom, to the consternation of Iida, Kacchan looks up from where he’s sitting, feet propped up on his desk,

chair balancing precariously on its back two legs. Their eyes meet and Katsuki immediately narrows his into a glare. Izuku breaks out in a nervous sweat, heat creeping into his face as he averts his eyes and shuffles over to his desk.

He doesn’t even manage his usual “good morning” as he takes a seat behind Katsuki, too busy *not* thinking about Kacchan saying thank you, Kacchan on his knees, Kacchan with Izuku’s cock in his—

“You have five seconds to be in your seats,” Aizawa drawls,

snapping Izuku out of his thoughts.

Everyone makes it to their desk in three, and lessons begin.



He almost makes it through the day without embarrassing himself. Almost.

“Young Midoriya!” All Might calls, walking toward him with Kacchan in tow.

Izuku freezes, wondering if it’s too late to abandon his solo practice and flee inside the dorms.

“A-All Might, Kacchan,” Who really doesn’t look happy to be there, hands shoved in his pockets, scowl fixed on his face, “did you need something?”

All Might let’s out a boisterous laugh that’s cut off by a bloody cough. “Young Bakugou and I were just discussing the benefits of having a sparring partner.”

Katsuki rolls his eyes. “And I already told you I don’t need help from a damn nerd!”

Izuku’s jaw flexes a little as he clenches his teeth, annoyed at Katsuki’s response. He certainly needed help yesterday when Izuku *saved his life*, but reminding Kacchan of that would just make him angrier.

“It’s alright, All Might. I don’t think sparring with Kacchan would help either of us,” he says with a nervous laugh, hoping that’s the end of the conversation. But when has Izuku ever been that lucky?

“What the hell is that supposed to mean, Deku?” Katsuki demands,

getting right up in his face. “You think I can’t show you a thing or two?”

Izuku pushes away thoughts of exactly what Katsuki can show him and waves his hands in front of his face, warding off Katsuki’s advance. “I just meant, you already work so hard, Kacchan—“

“HAH?! YOU THINK I CAN’T HANDLE A LITTLE EXTRA SPARRING WITH A SHITTY NERD LIKE YOU?!”

“That’s not what I…” But it’s already too late. Kacchan won’t rest until he proves his point, and Izuku finds himself being dragged away.

He shoots a desperate look over his shoulder at All Might, but the man just gives him a thumbs up and a toothy smile. Sometimes Izuku really wishes All Might wasn’t so invested in his and Kacchan’s friendship.

Once they’re in a secluded area of forest, a ways away from the dorms, Katsuki lets go of him and turns to face him. The way they stare each other down reminds Izuku of their fight at Ground Beta last year. Back then Kacchan had come out on top,

but now Izuku wonders how they’d end up.

“You ready for this, Deku?” Katsuki asks with a smirk.

No, Izuku thinks, but he readies himself anyway. He knows from experience that Kacchan won’t wait for an answer. Katsuki rushes toward him, bolstered by an explosion,

knee outstretched and aimed at Izuku’s gut. Izuku activates One for All just in time to dodge to the side, out of the way. He turns in place, fists up, ready to launch an attack of his own when he sees Katsuki stumble as his feet touch the ground.

Yesterday he’d taken a hit to the leg, but throughout the rest of the fight Kacchan hadn’t given any indication he was injured, and he’d shrugged off the medics that’d come up to them after the villain had been arrested. Apparently, the injury is worse than Izuku thought.

He frowns, taking a step forward, hand subconsciously reaching toward Katsuki. “Are you okay, Kacc–”

Katsuki whirls on him with a furious expression, palms crackling.

“Oh fuck off!” he roars, charging forward. Now that Izuku knows what to look for, he can see the slight limp

in Kacchan’s gait. When he’s close enough, he swings a fist at Izuku’s face.

Izuku ducks under the hit, leg sweeping out before he even thinks about it. Katsuki jumps to avoid it, but when he lands on his injured leg, he nearly falls again.

“Kacchan, stop it!” Izuku says,

voice caught between anger and desperation. Why is Kacchan always like this? Why does Izuku have to beg him to let him help? Is it really so hard for him to swallow his pride?

“I already told you, Deku!” he shouts, coming at Izuku in a whirl of jabbing fists.

He avoids using kicks, which makes his attack pattern far too predictable for Izuku, who’s been watching Katsuki fight since they were four years old. “Mind your own damn business! I don’t need help from fuckin’–”

Before Katsuki can even finish his sentence,

Izuku seizes both of his arms by the wrist and yanks him in close, yelling furiously in his face, “WHY CAN’T YOU EVER JUST BE THANKFUL?!”

For once Katsuki looks startled, eyes wide and explosions gone quiet. The only sound is their breathing, coming out in pants from the fight.

Izuku thinks he sees vulnerability in Katsuki’s eyes, but in a blink it’s gone.

Katsuki pulls his wrists out of Izuku’s grip and shakes his head. “Thankful? You want me to be *thankful*?” he scoffs. Katsuki leans right into Izuku’s face and lets out a mean laugh.

“Like what? You expect me to grovel?” Izuku opens his mouth to deny it, but Katsuki cuts him off, tone dripping with sarcasm. “You’re right, Deku. Thank you *so much*. What would I do without you around to keep me safe?”

Izuku’s mouth goes dry and he can feel his heart beating

hard against his ribcage. He knows Kacchan is making fun of him, but his body doesn’t seem to have gotten the memo. Blood rushes to his head and then seems to do a U-turn and go directly south instead.

“Kacchan…” he says, not sure if he wants to tell Katsuki to shut up or keep going.

“... fuckin’ looking down on me,” he continues, oblivious to the flush on Izuku’s face. “You think because you’ve got a fancy quirk now that you’re better than me? You expect me to kiss your ass

just because you’re not total deadweight anymore? Well news flash, Deku, I—“ Katsuki’s furious expression falters as he glances down. His gaze snaps back up to Izuku’s face, and his own cheeks flush red. “What the fuck?!” he shouts, “Are you hard?!”

“That’s…” Izuku says as he racks his mind for an excuse, “... just from the adrenaline.”

His voice sounds weak to his own ears, and one look at Katsuki’s skeptical expression confirms that he doesn’t believe the lie either.

“Wait,” Katsuki says, and to Izuku’s horror he can see Kacchan mentally piecing it together, “are you hard because I *thanked* you?”

He asks like it can’t possibly be true, but even as he says it there’s a mocking smirk tugging at his lips.

Izuku feels embarrassment crash over him like a wave, followed swiftly by anger. It’s not like he *wants* to feel like this.

“Gross,” Katsuki laughs, face smug with knowledge of yet another thing he can make fun of Izuku for. Izuku clenches his hands into fists at his sides.

“Is that why you wanted to become a hero so bad? ‘Cause you’re some kind of freak who gets off on it?”

Izuku knows Kacchan is just lashing out, acting like a brat to hide his own insecurity, but he’s reaching the limits of his patience.

The more he thinks about it, the angrier he gets. He’s done nothing but protect Kacchan their whole lives, even before he had the power to do it, and Katsuki still has the nerve to give him attitude.

“Shut up,” Izuku says, practically shaking with nerves but emboldened by

the anger burning in his chest.

“What?” Katsuki looks at him like he’s been slapped, and Izuku uses the momentary surprise to push his advantage. He advances on Katsuki and shoves him back against the trunk of a tree, birds fleeing from where they’d been sleeping in the branches

as the leaves quiver from the force of Izuku’s push.

“I said be quiet, Kacchan.”

Izuku doesn’t raise his voice. He doesn’t have to. They’re practically chest to chest, the position eerily reminiscent of his fantasy last night, except in reverse.

Izuku knows he should step back, play it off like a joke, make his excuses and run back to his dorm, then hope and pray Kacchan never brings it up again. But the air is charged with *something*, and Izuku can’t seem to look away from Kacchan. The air between them feels electric.

“You *should* thank me,” he says, not sure where the words are coming from. He wants to take them back, but they continue to fall from his lips like he’s been holding them in for a long, long time. “I saved your life yesterday.”

Katsuki stares back at him in disbelief,

speechless. Izuku leans closer and Katsuki shrinks back, t-shirt catching on the bark of the tree behind him. They’re practically eye to eye, Izuku only an inch shorter than Katsuki since the beginning of second year.

“I could have escaped myself,” Kacchan protests, but Izuku

doesn’t want to hear it.

“Then why didn’t you?” he asks sharply. Katsuki is silent, and it gives Izuku a sick sort of satisfaction to see him finally humbled. It’s something he never thought he’d want. Kacchan is his image of victory; he never gives up and never stays down.

That’s what’s so amazing about him.

But losing to *Izuku*, specifically, seems to be another story. Seeing Kacchan so off balance and unsure for the first time gives Izuku a heady rush. The tables have turned and Izuku feels *powerful*.

“You know what else, Kacchan,” he says, so close that their noses almost touch. He’s surprised Katsuki hasn’t tried to blow him up yet, but he seems just as caught by the tension as Izuku is. “I saved your life before that too.

Who do you think came up with the plan to grab you and escape at Kamino? Todoroki?”

Katsuki averts his eyes, lips pulled down in a scowl.

“No,” Izuku says, “you knew it was me. I had Kirishima reach out to you because I knew you’d never take my hand.

You’re so stubborn, Kacchan, so I let you have your pride, and how do you repay me?”

Katsuki turns his face away, refusing to look at Izuku as he says, “I don’t owe you shit.”

Izuku grabs him by the chin and forces his face forward until their eyes meet. Katsuki’s face is red from anger, and Izuku can feel his jaw flex as he grinds his teeth.

“Not even for saving you in Middle School?” Izuku asks, and Katsuki’s breath hitches.

He shouldn’t be saying any of this, but he can’t stop. Back then Kacchan had left him alone in a silent show of gratitude, Izuku knows. But it isn’t enough. It’s never been enough.

Katsuki’s face turns even redder, and Izuku can’t help but think how pretty he looks flustered

and angry.

“Keep dreaming,” Katsuki says, but Izuku can practically taste his shame, his guilt, his embarrassment at what they both know to be true. “All Might saved me.”

“Liar,” Izuku breathes. He feels dizzy with the sweet smell of Katsuki’s skin, the warm press of his body.

He knows Kacchan can probably feel how hard he still is, but he doesn’t care. And he doesn’t think Katsuki cares much either, because he still hasn’t moved away. “You just don’t want to admit you needed help from a quirkless Deku.”

Katsuki tries to shake his head, but he’s still caught in Izuku’s grip, so instead he bares his teeth. “I didn’t.”

“You did, Kacchan. The look in your eyes was begging me to save you.”

Katsuki’s exhale is shaky, and Izuku can feel it tickle over his lips.

When did they get so close?

“I don’t beg,” he says, but he doesn’t sound sure and his pupils are so wide there’s hardly any red left.

Izuku can feel something distinctly hard pressed against his hip, and he licks his lips. Clearly Kacchan likes this too. Does he want to beg? Does he want Izuku to *make* him?

Izuku steels himself and decides to find out.

“You will,” he says, and to his shock Katsuki moans. It’s quiet, barely audible above the rapid thump of Izuku’s heart and the night rustling around them, but the noise goes straight to Izuku’s cock. He doesn’t think he’s ever been more turned on in his life.

“Kacchan,” he whispers, the fingers curled around his jaw loosening into something more tender as he cradles Katsuki’s face.

Katsuki doesn’t move when Izuku leans in and kisses him. He’s stiff as Izuku presses him back into the tree, like he’s never been kissed before.

Maybe he hasn’t, Izuku thinks, and he feels something possessive well up in him. He wants to be Kacchan’s first and his last; he wants to be Kacchan’s everything.

For a moment Izuku thinks Katsuki won’t respond, but then his hands come up to grip Izuku by the biceps

and he kisses back. It’s a little clumsy, but Izuku doesn’t mind. He’s far too busy memorizing the taste of Katsuki’s mouth, and the way his fingers feel pressing into Izuku’s skin. They kiss, and kiss, and kiss, and by the time Izuku pulls back Kacchan is flushed all the way

down his neck, breathing hard. He looks dazed.

“... the hell did you learn to kiss like that, nerd?” Katsuki demands.

Izuku kisses him again instead of answering. He can tell Kacchan likes it from the hungry noises he makes against Izuku’s mouth, and the way he lets Izuku lead

without even realizing it, going slack against the tree as Izuku sucks at his tongue until Katsuki’s clinging to him.

He runs a hand up the back of Kacchan’s shirt, tracing his spine with the tip of his index finger until Katsuki’s arching away from the trunk and pressing

right up against Izuku with that perfect body. Izuku can hardly believe he’s never noticed it before. Now he can’t stop staring at the swell of Kacchan’s chest just below the neckline of his shirt, can’t stop squeezing his waist just to savor how tiny it feels in his hands.

“You better not tell anyone about this, Deku,” Katsuki threatens breathlessly as Izuku kisses down his neck, sucking a hickey into his skin as his hand slides lower to squeeze Katsuki’s ass. Kacchan’s so small here too, only a little more than a handful, and Izuku can’t help

but think of how Katsuki might look bent over, struggling to take his whole cock.

“I don’t know, Kacchan,” Izuku replies, nudging Katsuki’s legs further apart with his foot. He settles between them and drops his forehead to Katsuki’s shoulder. “You’re not asking me very nicely.”