Izuku, and it leads to him getting jumped!

There was a laugh, and a voice called, "I'll save you!" That was all the warning Markus heard before he heard wet feet on the concrete.

Markus yelped as Izuku jumped onto his back, and he was dunked. Ochaco and Mira giggled as he came back up, sputtering. "Oh, it's on now!"

"Jump him!" Ochaco declared as she swam at him.

"Wait, what?" he yelped as all three proceeded to gang up on him.

Markus— the supposed Master in this situation — found himself outmatched in watery combat. He was the biggest and strongest here, though not by much, with Izuku being surprisingly muscular, and the girls targeting his weak points with a giggly viciousness that left him disoriented.

Mira's main goal had been to get everyone naked again, and she had swiftly succeeded. Pulling and plucking at swimsuits until there were no barriers between wet skin.

Soon, the wrestling slowed and the laughter became interspersed with moans as hands grabbed at cocks and tits, and lips met in kisses. The four soon decided it was time for more fun.

"Mira..." Markus gasped as he pinned Mira from behind, his cock rubbing her inner thighs. "I wish the water wouldn't interfere, even assist with any natural lubrication."

"Granted!" she immediately gushed.

"So much for you being able to restrain yourself. I really shouldn't have jinxed it," he grumbled playfully to himself as he led them all to the shallow end. "...you brought what's coming on yourself with your response regardless," he then told Mira.

"By design, Master," she purred. "What's coming?"

"...you have three holes, and we got three dicks between us," he remarked.

Mira bounced on her toes in the water, smile almost blinding. "Yesyesyes! Fill me up! Hehehe! I can be made airtight underwater~"

Izuku raised a hand. "Um, how are we gonna manage this? Won't one of us basically have to be underwater for a while?"

"...good point. I wish everyone in the harem could hold their breath indefinitely so long as they're having sex."

"Ooh! That has lotsa possibilities! Done!" Mira bent forward and shook her hips, showing how both of her lower holes were ready and waiting.

All of them sucked in a breath as their lungs tingled, the wish changing them. Ochako immediately tried holding her breath, her puffed cheeks quickly reddening, then she lost all strain when she fondled Izuku.

"This is so cool!" she cheered.