Growing up, Kacchan's voice was nothing special.
Just as high pitched as any other child's, just as grating. But Deku loved it anyways, always eager to hear him talk about anything and everything.
As they grew up and began puberty, his voice began to break, going from high pitched to deep in fractions of a second. It was nice when it was high, but when it was deep...when it was deep, it twisted something deep inside Deku's belly.
Then one day it deepened and stayed that way. That was probably the worst day of Deku's life if he's being honest.
Suddenly always being surrounded by that deep, growling voice did things to him. Things that he couldn't do anything about until late at night.
The first time he had given in to these urges, he had fought them for a long time, tossing and turning in his bed for hours, careful to keep his literally leaking cock from brushing against the bed as Kacchan's rough voice echoed in his ears.
The sweet relief when he had finally given up and started to stroke himself had rung tears to his eyes, his sobs muffled by his pillow as he shivered into a bone-melting orgasm.
'Just this once', he thought to himself as he finally fell into darkness.
The next day, 'just this once' became 'just because I'm already hard'.
'Just because I'm already hard' became 'just because I can't sleep'.
However, he didn't realize it was an actual thing until a few weeks after that when Kacchan pushed him up against the lockers after class.
"Don't think you're gonna win," he had growled, low and hot in his ear in a way that caused goosebumps to break out along his skin. "I'm still gonna be Number One."
He had left after that, unaware that Deku was shaking and rock hard where he was pushed up against the locker.
Like every other thing in his life, he fell into research to find out what the hell was going on.
'I like voices???'
'Voices turn me on'
Turns out it's a real thing, being turned on by voices.
And he was turned on by one voice in particular.
Another real thing is not erasing his web history. He's never had to because his mom respected his privacy and didn't go through his things.
So when he walks into his room one day and sees Kacchan laying on his bed, on his laptop, casually scrolling, he freezes.
"Voice kink, huh?" The blond drawls, red eyes glancing at him for the briefest of seconds before focusing on the screen again. "What a little fucking perv. You're already on thin ice just by being in this school, now you're getting your rocks off to someone's voice?"
Deku swallows hard, the tone of the other's voice going straight to his cock as always. "T-that's not very nice, Kacchan," he replies weakly, closing his door and heading over to his desk, where hopefully he could conceal his already throbbing arousal.
Bakugou scoffs. "What's 'not very nice' is the fact that you're jerking your dick to some dude and his unsuspecting voice. Who is it, hah? Todoroki? You squeeze your little cock for that half and half bastard?"
He busies himself with taking his math homework from his bag.
"I don't think that's any of your business," he replies stiffly, praying to every God he knew of that the blond would let it go. Gods that apparently didn't exist, since not even ten seconds later a rough hand, was slamming down onto his desk, a warm body at his back.
"You are my business, Shitty Nerd," the other growled, anger causing his hand to spark, leaving a scorch mark on his desk. "Now answer my fucking question."
"I don't wanna." Fuck, his voice was shaky. Having Kacchan talking directly in his ear like that was quickly killing him.
Quicker than he could comprehend, he was pulled from his chair and slammed against the wall, Bakugou invading his space with his lips twisted in a sneer.
"You may not wanna, but you're fucking gonna. Who is it, nerd? Tell me!"
He was getting closer with every word.
Deku was trapped, wide green eyes flicking all over the room as he pushed weakly at veined arms. "N-no! Get off me!"
"Listen, Shitty Nerd, I-!"
Deku moaned, his head flying back.
During his last outburst, Bakugou had shoved up against him all at once.
Which meant that he could distinctly feel the hard outline of Deku's cock pressed against his stomach. He was at a loss for words for a moment, staring wide-eyed down into bright panicked green eyes before a sadistic grin took over his features. Deku paled.
He was doomed.
"Oh, so that's how it is?" Bakugou asked, his hands gentling until he was petting his chest gently. "Is it my voice you think of, nerd? Don't lie."
"No," Deku immediately lied.
"Oh, really?" Bakugou ducked down, ignoring his squeak of surprise as his lips ghosted his ear. "So if I talk just like this," he whispered, causing Deku to almost burst into flames right then and there, "it wouldn't have any effect on you?"
Bakugou hummed, pressing his own now very interested crotch against the other's equally interested crotch. "You sure?"
Deku whimpered, his legs almost giving out on him. Bakugou's voice on a normal day was deep, but it was never this close, never with hot breath brushing along his ear, making his cock leak all over the inside of his boxers.
Deku moaned out loud, his legs losing all strength immediately, causing him to collapse in the blond's strong arms. "D-don't-!"
"What's wrong, Izuku?" Bakugou asked, all smug grins as he grabbed two handfuls of that perky ass and squeezed. "Isn't this what you wanted?" He cooed softly in his ear, placing a kiss just underneath it as he bodily picked up the smaller male and carried him to the bed where he could properly touch him.
Deku's needy whine was loud, his fingers tangling in the sheets on instinct.
Bakugou hummed, biting into the soft flesh of the green-haired man's earlobe as he used his grip on his ass to properly grind their hips together, gaining a wail of pleasure as his reward.
"You're making such slutty sounds, Deku," he rumbled, his voice dripping with lust. "Is this how you imagined it when you thought of me? When you wrapped your hands around that hard little dick of yours, did you imagine me holding you down like this, having my way with you?"
Deku could feel himself tearing up as the pleasure mounted. "Y-yes!"
"Hah? Fucking slut," the blond huffed in his ear, his voice becoming ragged as he chased his orgasm in a way that made him let out the filthiest moan. "What would our classmates say if they knew you were such a greedy whore?" He mumbled, his hands leaving bruises on pale hips.
Deku's laugh was almost hysterical. "Y-you think they don't? Like I c-can keep a secret like that. The only one who didn't know is you."
"Guess I better make up for lost time then," Bakugou replied after a beat, catching plump lips in a kiss.
And suddenly its as if everything escalated tenfold. Bakugou was moving his hips faster, using the grip that he had on Deku's own hips to maneuver him where ever the blond wanted him.
And fuck, it was hot.
Not only the situation but Bakugou.
The way he was huffing and grunting in his ear after they broke the kiss, loud and unrestrained, had Deku harder in these few minutes of time than he'd been in his whole fucking life. His own whimpers and cries intertwining with the other in a lustful symphony. His orgasm blindsided him if he's being honest with himself. But that's only because Bakugou surprised him. The blond had let out an absolutely filthy moan as he grinded against him, his hands tight on his hips as his name rolled off his tongue in that deep voice.
And yeah, he might have the power of One for All, but he wasn't fucking Superman. He came literally seconds later, his own moan loud and unapologetic as he stained the inside of his boxers with a thick load of cum.
And then, Bakugou bites him.
Digging those perfectly white teeth deep into space where his neck meets his shoulder hard enough to leave a mark as he reaches his own orgasm, a growl of completion rumbling in his chest.
And Deku's not saying he could die happy right now, but goddamnit he's thinking it.
The room is suddenly silent but for the ragged breathing of both boys as they struggled to pull themselves back together. Finally, Deku pokes the blond in the ribs.
"Kacchan, you're heavy! Move!"
"Make me, nerd."
Deku's eyes narrow. "Sounds like someone's forgotten about The Claw of Doom."
A pause. Then...
"You better fucking not."
Deku flips them, his hands already digging into Bakugou's armpits. The blond squeals, slapping at his hands as laughter is forced from his mouth.
"Stop it you fucking asshole!" he yells between laughs. "It’s not cute when there's cum in my fucking underwear!"
Deku pauses, cocking his head to the side curiously. "So you're saying it’s cute without cum in your underwear?"
Bakugou frowns (pouts) and looks away.
"Whatever, fucking nerd."
The green-haired man grins.
"I think you're cute, too."
Bakugou scoffs. "Oh yeah, the hard dick you had pressed up against me a little while ago shows me exactly how cute you think I am."
Deku flushes, sputtering.
"W-well, you were hard, too!"
"Hah?? It was a pity erection!" The blond yells back, bopping him over the head with his pillow. And as they descend into petty squabbling, Deku thinks that it probably was always gonna turn out this way for him.
After all, it had always been Kacchan.