Chapter Text
Izuku sat in his bed sighing and rubbing his arm as he stared at his All Might poster waiting for Kacchan, whom he had begged to let him give him his number, to text him. When it finally pinged, after a moment he nearly fell off his bed reaching for the phone.
Kacchan 😊😊: Is this the nerd?
The text came through. Izuku giggled; Kacchan is so silly! He was so excited when, after their training today, Kacchan finally agreed to give him his number. He’d been insecure about their friendship since the day they both started at U.A. The idea of their whole relationship being based on rivalry made him insecure; what if one day that wasn’t enough? So when his Kacchan finally agreed to become texting buddies, he was over the moon; he’d finally get the chance to prove how awesome of a friend he could be!
You: Hi Kacchan! :)!!!! was worried I got my number wrong when I wrote it down!!!
Kacchan 😊😊: Stupid nerd. Quit it with the exclamation; it’s like I can hear your stupid voice.
You: Kacchan!! Don’t be mean; I’m injured! remember!
Izuku giggled, rolling onto his back. He was only slightly joking; he’d never lie to Kacchan! When they were sparring, Katsuki delivered a harsh explosion to his arm before he could block it. making it rather sore to the touch, or movement, or even looking at it! It wasn’t that bad, but he just wanted to hear Katsuki worry over him nonetheless.
Kacchan 😊😊: Tch, I forgot you were that weak. If a tiny explosion is all it takes to destroy you, I’ll pass you easily!
Katsuki scoffed at his phone. only slightly worried, he knew the nerd was just exaggerating. He could take him and keep up with him. Katsuki was sure of it.
Deku: Kacchan… Don’t you feel bad for me!
Katsuki opens the message to see an image attached. Izuku is staring up at the screen with his lip puffed out and his bare chest and arm red from taking Kacchan's explosion. He feels himself twitch and reels back in shock. Glancing at his pants, he looks back up at his phone slowly. What is Deku playing at? Whatever it is, Katsuki will win for sure.
Kacchan 😊😊: Getting injured from a lowly explosion isn’t enough? You have to send a slutty shirtless picture to gain my—what, sympathy?
Izuku drops his phone with a shriek. Did Kacchan really—? He picked up his phone, flipping it over. HE REALLY SAID IT! He looks at his picture again, confused. Slutty? Maybe he should’ve put a shirt on, but it wasn’t the first time Kacchan had seen him this way.
Deku: Maybe you’re just being a pervert, Kacchan. I wasn’t doing anything!
Katsuki grumbles a laugh. him?? the pervert???
Kacchan😊😊: Pervert? says the nerd who has notebooks filled with facts about me. Including my shower schedule…
Deku: KACCHAN!! You said you wouldn’t mention that! Plus, it’s not like I was—well, your sweat is important to your quirk, so I had to know if you need to shower more because of that or if it’s only your hands that are explosive!
Izuku shoved his head in his pillow. Kacchan wasn’t supposed to remember that darn it!
Kacchan 😊😊: Yeah, yeah, pervert probably watched me shower too. Did that get you going? write down the measurements of everything, did you?
Izuku gasped. Was Kacchan flirting with him? well, as best as Katsuki could flirt. Izuku blushed so hard he could’ve sworn all the blood in his body was in his face!
Deku: NO! I would never invade Kacchan's privacy like that!! unless he wanted me to! and I wasn’t being... slutty! •\\\\• I just wanted Kacchan to feel bad for injuring me!!
Kacchan 😊😊: Tch, nerd. Don’t act like you weren’t too distracted by my arms, and that’s why I got that hit on you. You were practically drooling.
Izuku is basically dead at this point. He has to be; otherwise, there is no way Katsuki would text him this—this provocatively! There is no way he has to make sure he isn’t misreading things!
Deku: And so what if I was Kacchan?
Izuku puts his phone down, covering his face and glancing at it through the cracks between his fingers. Typing bubbles come up then disappear; Izuku begins to type out an apology when a photo comes in instead.
It’s Kacchan based on the room and decoration, but the only thing in the picture is his arm. Izuku lets out a gasp before pulling his phone towards him just in case peering eyes might find the picture meant just for him (he’s literally alone in his dorm room, with the door locked…). The arm in question is being flexed, showing off the array of muscles Katsuki has built up over the years. Izuku thinks that all the blood that rushed to his cheeks is now somewhere more southern and pulsing in his pants. This also confirms his theory! Yes, he must be dead! There is no way! or maybe Kacchan has been kidnapped or—
Kacchan 😊😊: I know you are a literal perv, but I didn’t think one picture would silence you.
Right, he totally forgot to reply! What does he say?
Deku: SORRY!! ☺️☺️ I got a little distracted; Kacchan is so strong!
Kacchan 😊😊: Yeah, yeah...
Izuku stares at his phone unsure of how to reply. Kacchan seemed... unsatisfied with his earlier reply. had he expected more? He normally loves to hear himself be complimented!
Deku: Kacchan… Can I tell you something? The picture actually... um, it made me hard. •\\\• DON'T GET MAD!
Katsuki sits up in his bed. Is this—they, are they about to? It’s probably fine; Kirishima says it’s manly to help out friends (totally not what he meant). Izuku is his friend now, so could he help him with this?
Kacchan 😊😊: Did it now? I don’t believe you, Deku.
Izuku blushes; Kacchan seemed more into this reply. He must prove he wasn’t lying, angling his camera down...
*Deku has sent an image.*
Deku: See, Kacchan! SORRY!!
Katsuki groans at the picture, gripping his phone harder, one hand sliding down to squeeze his growing bulge for some relief.
Kacchan 😊😊: Poor Deku, what are you going to do about it?
Deku: What does Kacchan want me to do?
Kacchan 😊😊: Can I call you?
Izuku Let’s put a little gasp. Is this okay? It’s just something friends do to help each other out; Sero and Shouto do it, so it must be fine!
Izuku hesitantly reaches down and lightly traces his erection, teasing himself till Katsuki calls. The sensation is so light through the layers he’s wearing.
He gets so distracted with the frustrating light pleasure he feels he doesn’t even notice Kacchan is calling him.
“kacchan?” he whispers into the phone, bucking into his hands. “Deku, are you? touching yourself?” Kacchan's voice asks roughly with a hint of hesitation, “Yes, it feels good..." couldn’t wait” Izuku wants to reach under his basketball shorts so bad, but he wants to let Kacchan take the lead. “That’s good; just keep lightly touching; I want to tease you.” Izuku lets out a sweet whimper.
His light gasps and huffs are heard in the mic for a few minutes before finally, “Please, Kacchan! I need more; it's too hard; it hurts!" Katsuki lets out a dark laugh at that. “Go ahead, go on top of your underwear, Deku; I’ll let you have one layer.” Katsuki's smug attitude drops when Izuku replies with, “‘m not wearing any underwear!" Something in the background pops open with a click. “Fuck ‘zuku, you trying to kill me?” Izuku hears another soft sound in the background and perks up with a gasp. Is Kacchan touching himself because of me?? “Please, Kacchan, let me touch myself; I need it!” Katsuki lets out a light groan. “Go ahead, baby, touch yourself nice and fast; don’t stop till I tell you.”
Izuku gasps softly, taking himself in hand, finally his cock red and achy. He can't believe this is happening, that Kacchan is letting him do this, is doing this with him. His heart races, his whole body tingling with anticipation and arousal."Please, Kacchan," he whimpers, not sure what he’s begging for. The fabric is already damp with precum as he gets a rhythm going. "I-I need it so badly..."
Izuku starts rubbing himself faster, panting and moaning softly into the phone. His cock throbs almost painfully, desperate for more friction. But he tries to hold back, to draw it out like Kacchan told him to at the beginning. "I'm t-touching myself, Kacchan," he reports breathlessly. "Feels s-so good... Ahh! B-but not enough..."
“You need more? tch. Of course you do, you little slut. never satisfied.” Izuku makes a noise in between a whimper and a moan, “Yes, Kacchan, please, need more!”. “Fuck, okay, do you—do you have lube? like, have you ever?” Katsuki grumbles out the rest, his hand pausing in the slow strokes he was trying to get relief with. The reply comes hesitantly, almost missed if Katsuki wasn’t locked in on every noise coming from his phone's speaker. “Yeah, I have.” added louder is “BUT LIKE not in a weird way. like it just feels good!! I'm not like gay..." "Yeah, just helping a friend out.” “it’s fine Kirishima even says so. Kirishima… Izuku wonders who was talking about him. Kacchan only needs to focus on Izuku. I mean, Izuku was the one he was supposed to be helping. “Now tell me what to do, Kacchan; I want to hear you say it.” Katsuki feels a weird feeling settle in his chest but pushes it aside.
A few moments later, Izuku has two fingers inside himself, his phone on speaker on his pillow, and a slew of words coming out of his mouth. Most words are unintelligible compliments, moaning, whimpering, and whining about how much Kacchan is the best, how he wishes he were there, how cool Kacchan is—Kacchan, Kacchan, Kacchan. Katsuki is barely keeping it together, his grip now tightened at the base of his dick, determined to not cum before Izuku. “‘Zuku baby, fuck, twist your fingers. find that spot, wanna hear my slut cum. Izuku shivers at the possessive term. “Yes, okay, Kacchan, okay, okay!” He twists his fingers searching for that one spot inside himself; when he finds it, he doubles over in his bed with a cry for Kacchan.
Katsuki finished right after with a resounding groan.
It’s quiet on the phone call, neither one sure how to segue into the next topic. “So training was okay for you?” “Yes, Kacchan! I love training with you!” “Good, well, it’s late, so good night, Deku.” “Good night, Kacchan. Thanks for helping me.” “SHUT UP.” With that, the call ends, and Izuku feels light and sweet. Although one thought has his body slightly tense, what did he mean by ‘Kirishima said it’s okay?’