Chapter Text
Katsuki was running to his room, trying to keep the urine in his bladder as it screamed for release even when he had the chastity secured. He shouldn’t have drank those three cans of orange juice at lunch, but he was damn thirsty after consuming salty fish Iida had made for him. The blonde knew Four-Eyes did it on purpose, kinky bastard.
“F-fuck…” He moaned, pressing the chastity a bit as he could feel it push out from the pressure. He tightened the strap a little more and cleaned up the little urine that leaked out. “This better be worth it, otherwise he will not get another chance until the end of the school year.”
Changing into his normal clothes and grabbing his prep bag, he waited for the other extra’s to return to their room before he left and quickly headed to Iida’s room 2 floors down. Wearing socks to reduce the noise of his steps, so none of them would go and nose around. The only thing he had to make sure was to pay Ears a list of music she wanted to keep her silence and make sure the nosey bitches were out of his way.
“Hey, Kacchan!”
Katsuki jolted several feet and had to pinch his legs to prevent his bladder from leaking once again. He turned around and glared at his childhood friend, who happened to have a prep bag of his own. “Who are you fucking tonight?”
Izuku sported a tick mark on his head. “Stop making it sound like I’m a slut, Kacchan. I am spending the night with Kaminari tonight. He seemed pretty down when someone destroyed his bento full of watermelon.” He saw Katsuki growl and nod as he too saw Monoma and his gang destroy Pikachu’s bento. “I am hoping to cheer him up with some foreplay, which from what I can tell, you are planning some fun too.” The verdanette smirked and pulled out a large water bottle, shaking it to produce sloshing sounds. “How long has it been since you drank that juice?”
The blonde’s eyes widened as he tried to control his bladder again, the water triggering his reflexes. “You fucking bunny nerd, you are doing that on purpose.” He flipped him off when Izuku cackled like a madman. “Go fuck your boyfriend already!”
“Already planning on it, just make sure you don’t piss all over him when you have fun too.”
“You better go before I blast you to oblivion!!” Katsuki harshly whispered, releasing small blasts at the retreating verdanette. “Fucking hell, Deku, I’m already under pressure as it is, I don’t need you riling me up tonight.”
Katsuki sighed again, leaning against the wall as he pinched his thighs together, willing his bladder to stay inside. He could feel his prostate throb uncomfortably, yet…why were his coils tightening? Like his prostate was being pressed for so long, it now began to feel pleasing, except for the full bladder part.
“Mmph!” Katsuki put a knuckle in his mouth and bit down, his body tensing as a larger pulse caused his hips to buck. He scrunched as his face and neck flushed, both in arousal and embarrassment that he almost got caught. Thank god the chastity held, otherwise he would be pissing all over himself.
He paused the moment he thought that, at first feeling disgusted by the thought of it, but the thought of the relief afterward, somehow made his cock throb, as if it sounded appealing to him. “Motherfucker…don’t tell me I have a pissing kink.”
Taking a few stumbling steps to test the waters, so to speak, he finally reached Iida’s room, looking around before entering. He couldn't wait to get it over with, as he needed to piss, now. “Okay, four eyes, you better be prepared for death, because I have to piss like a horse.”
Iida chuckled, watching Katsuki strip as quickly as he could. The chastity held pretty good, and his cock was swelling with both an urgent need and arousal. He pressed the pelvic pouch right above the chastity, feeling him flinch as his bladder squeezed. “Yes, you are pretty full, too full for what I have in store.”
Katsuki growled, seeing him pull out something in his dresser, eyes widening at a large syringe. It looked like it can hold 150 mL, one fifth of what Katsuki’s bladder is currently holding. “You fucking serious….”
“Would you rather I’d fuck you now, I can’t guarantee the bladder won’t burst.” Iida said, looking at the blonde with a look of dominance, smirking as his boyfriend shuddered.
Katsuki clicked his tongue, hating the fact he was at Iida’s mercy, yet loved the switch in power play. He stood still as the bluenette did his thing, twisting the syringe to connect it with the chastity, before slowly pulling the plunger out, the hot golden liquid filling the chamber. The blonde’s blush deepened as he watched, his breath coming short as he watched and slowly felt his bladder’s pain lessen. “Oh, fuck…”
Smirking, he removed the syringe, keeping the chastity on Katsuki as he watched the flushed expression. Now that the bladder is somewhat relieved, it was time to have fun. He kissed Katsuki tenderly, rubbing the blonde’s ass with a thick ointment, working his fingers as Katsuki bucked at the stimulation wracking his already sensitive insides.
Katsuki moaned, parting his lips as Iida dominated his mouth, his thick hands working expertly inside his ass. The pressure in his bladder was stirring, increasing the throbbing heat of his prostate was already building. The moans slowly became whimpers as his cock throbbed hard, painfully still within the confines of the chastity, and bucked hard as semen leaked from the rod inside him. Gasping as he suddenly pulled away from Iida’s mouth, he held his stomach as the bladder throbbed again, forcing some urine to leak from the same rod. “F-fuck, I need this off, now…”
“I guess we can speed things up.” Iida agreed, unlocking his belt but kept the rod inside. He waited for Katsuki to straddle him, wrapping his arms around Iida’s arms as he tried to position the bluenette’s thick, long cock. He kissed Katsuki’s neck, slowly sliding him down his length until he got to the hilt.
Katsuki gasped deeply, that massive cock of his boyfriend was splitting him open, like it normally did, but his body was convulsing at the new sensation that added to his arousal. It was pushing his bladder to the front of his pelvis, his prostate screaming in both pain and pleasure, and it was making his legs shake. “I-Iida, fuck…so deep, it feels bigger than before…”
He slowly rocked his hips, testing the new stimulation that was not only making his coils taught, but it was hot and pleasurable, it was like the full bladder was increasing the pleasure. Katsuki moaned deep, now rocking his hips up and down as he seeks more of that body-splitting sensation. “F-fuck…so painful…so good…your cock is fucking huge…”
Iida was holding his hips as Katsuki continued to slam into him, the squelching slaps as his ass bears the brunt, tears prickling at the edges of the blonde’s eyes as he reaches closer to the climax. “You look so hot, what do you want?”
Katsuki wheezed, trying to speak as his body tenses, his legs shaking from the movement and depth. “I-I need to pee, I need your cock…your cum….please…let me cum!” He then yelled as he got forced down, his prostate and bladder pressed so hard and deep that his body exploded, seizing from the orgasms that were out of this world. “O-OH, GOD….I’M CU-!!”
Iida pulled the rod out of Katsuki’s cock, and his piss was shooting everywhere as Katsuki seized, cumming with his eyes wide open, silent screams as the breath left his lungs. The bluenette smiled wickedly, his operation of omorashi was complete, and seeing Katsuki pissing all over the two of them was hot, Katsuki eventually mewling as he then released his seed in the blonde’s ass.
Katsuki slumped over, relieved that his bladder was finally empty, and squirming a little as he felt Iida’s seed inside. It felt amazing, and he didn’t want to go back to normal sex after that. Double the pressure was worth double the orgasm.