Give him a blow job

Hana stares a little too long, and Yamamoto-sensei notices. He looks down at his own bulge and blushes, trying to hide it. “T-that wasn’t too bad!” He stutters, hoping she hadn’t noticed. “If we can practice your technique you’ll be able to swim a lot faster, without wasting so much energy, so you won’t be as short of breath either.”

Hana laughs a little nervously. “You’re too generous, that was pretty bad.” She looks up at him again. His bulge is only getting bigger. She can see he’s staring at her glistening body, and she feels a strange surge of power.

“Are you getting in the water too, Sensei? You’re wearing your swimming trunks.” She asks him innocently.

“Ah, I thought I might demonstrate, yes.” He sees the out she has offered, and kneels down to slide in. He is standing next to her now, his bulge mostly hidden by the water. But Hana is curious now.

“Let’s start with the basics and go over breathing techniques. Let’s see how long you can hold your breath.” He had meant it as a learning exercise, one he uses to prove to his students that proper breathing is important. He didn’t think it through.

Hana sees her own opportunity and immediately takes a deep breath and ducks her head under. She opens her eyes to stare directly at his bulge. She wonders how big it must be to be so obvious. She moves gently towards him, her heart beating like crazy. She didn’t have long to make her move, holding her breath like this. Hana gulps, then slowly slides his trunks down so his hard cock pops out.

Yamamoto-sensei takes a shocked step backwards, but Hana is already wrapping her lips around his head. She slowly blows air out from her nose as she forces his cock inside her mouth, so she doesn’t breath water. Yamamoto tenses up, and above water lets out a shocked moan. Hana is not brave enough to pump his cock underwater, and instead slowly pushes it as deep inside her throat as she can, wrapping her tongue and mouth tightly around it as she holds her breath. She enjoys the taste inside her until she feels her lungs tightening, and pulls him out, emerging for air.