Spocon!

Based on the erotic game by Astronauts Alya.

Tatsuya excelled at multiple sports disciplines during his school years to the point of being called a genius, but wasn't able to focus on a single discipline and become a professional. Now instead of being an athlete, becomes a coach at his former teacher’s school, Josho Academy. Highly anticipated by the school and the students, he is told he has two weeks to pick one club to coach and the competition between clubs over him starts.

However, the student council president as well as the club president of the swimming club, Katsumi. seduces him, spreads rumors and shows off the seduction in order to lit a fire under all students as she wants improve the school's lazy atmosphere.

(Source: Visual Novel Database)