It takes a long while

Ochaco pulled back her hips, shuddering as she felt her cock get exposed to the air again. She slammed it in again, eliciting a loud moan from both her and her genie. Izuku's ass was tight, but not too tight. Maybe it was because he was a genie. Maybe it was because her cock was still lubed with his spit. Maybe it was from all the pre-cum she was leaking. All she knew was each thrust got easier, and thus she got faster, and thus she could go harder.

"Ugh! Ugh! Ugh! Mistress~ Pound my ass! It's yours! It belongs to you~!" Izuku moaned.

Ochaco grabbed and kneaded his plump cheeks as she thrust. "Yeah it does! Oh fuck! I feel like I'm gonna cum already!"

"Do it, Mistress! As much as you want, remember? Fill me...fill me..."

She slammed into him and groaned as her balls drew up and she started firing her thick load into his ass. She spurted again. And again. And again. It felt like she was cumming for a full minute.

But she still wanted to keep going. And per the wish, that meant she was still hard, and still had the energy to fuck some more.

Ochaco wrapped her arms around Izuku's waist and started pounding him again. It wasn't slow, deep thrusts this time; it was a rapid, lustful pumping. She jerked herself with his asshole, beating her meat in and out of his tight bubble butt. It wasn't long until she came again, just as violently as before.

She lay down on top of him and started fucking him again. Izuku turned his head around and kissed her as she thrust and panted like a horny animal.

He knew Ochaco had told him he didn't have to talk dirty for her, but he also knew she might like it.

"More...more Mistress..." he panted, his hot breath hitting her face. "Do you like cumming in me? Do you like filling me up again and again? I love it, Mistress. I love how you use me. Please, use me more. Cum in me. Cum in me more!"

"Izuku! Ugh~!" Ochaco came again. "Holy fuck...every orgasm feels like my first one..."

"How about some more firsts then, Mistress?"

"Huff...I think I'm falling in love with you, Izuku," she grabbed her thigh and started to turn him over. "Or at least I'm falling in love with your ass."

She turned him around without pulling out. She noticed thick jets of cum across his belly and staining her sheets. Had he cum every time she did? That was pretty hot.

Ochaco touched her chest and started floating. She grabbed both of Izuku's ankles to stop herself from raising off. The genie looked up at her, his face a deep blue. He knew what she was thinking and he nodded. His cock twitched. His anus twitched around her cock. He was quietly begging for it.

Ochaco slammed her full length into Izuku's ass. The genie boy's mouth opened in a silent scream. She did it again. And again. On the third slam his cock started firing jizz onto his stomach and the underside of his chin. Her pounding got faster. She came again, but this time kept thrusting through the orgasm so her seed spilled out and drenched Izuku's balls. She fucked him like this through three of her own orgasms and four of his. Izuku by this point was in full ahegao; cheeks flushed, tongue out, eyes rolled back in his head, and his own cum all over his face.

She'd cum so many times in Izuku's ass that there was no friction at all anymore. Her hips were a blur as she slammed her whole length as hard and as fast as she could go. She should've been satisfied by now, but seeing Izuku's fucked-stupid expression made her never want to stop. And that wasn't all. Every time Ochaco came it was like half a cup at least. Quite a few times her pussy squirted alongside her spasming member. Cumming felt so~ good! It gave her an idea.

"I-Izuku..." she managed between manic thrusts. "I...I wish for us to cum non-stop for the next hour!"

The last coherent thing Ochaco heard was the snap. Then all there was was their joint screaming in pleasure. Ochaco released her quirk and fell on top of Izuku, his cock producing a constant stream of cum as it rubbed between their soft bodies. Ochaco's dick wouldn't stop either. That initial huge burst of pleasure from release just kept going, being dragged out as she fired an unending river into Izuku's ass. It was soon overflowing, but the couple didn't care. They moaned into each other's mouths as Ochaco continued to fuck him with her cumming dick. Izuku's seed shot out between her breasts like a geyser, and the two eagerly licked it off each other's faces.

It lasted an hour, as per the wish, but the two weren't consciously aware of it. Time ceased to have a meaning when the only thing on their minds was the pleasure of a euphoric, endless release. But eventually it did end, and the two lay panting in a room covered in their combined fluids.

"Maybe..." Ochaco panted as she saw she didn't really have a foot of her bed anymore but just a waterfall of cum. "Maybe...that was a little too much...I wish our mess was cleaned up..."

Izuku snapped his fingers and it all disappeared. Even the cum on themselves was gone. "Are you...satisfied, Mistress?"

Ochaco awkwardly giggled. "For now...I...never imagined that could be possible. I've seen some stuff and read some stuff online about excessive orgasms and stuff, but to actually experience it..."

"What did you think?" her genie asked.

"I think it could get addictive. But I do want more normal sex, too..." Ochaco sighed sleepily as she nuzzled into him. "I meant what I said earlier. I'm already starting to really like you, Izuku. It's going to be fun having you around."

Izuku smiled. "I live to please, Mistress," he said and kissed her forehead.