Shiofuki Mermaid

Makoto is an ordinary university student who frequently visits a local swimming pool to swim and watch women in swimsuits. One day, he is asked to teach a girl named Marina how to swim, as she seems unable to do so at all.

While giving her lessons, Makoto's hands wander over her body, and he becomes aroused. Marina notices his erection and responds by giving him a blowjob. When he touches her vagina, she cries out in pleasure and achieves female ejaculation. This awakens his unknown erotic ability, and he soon discovers he can make any woman—from a university student to a married woman—ejaculate with his fingers.