Kyonyuu Do Sukebe Gakuen ~Shoujo-tachi no Tomaranai Koshi Tsukai~ by Interheart - Adult Sex Game

One day on train the protagonist is able to hear conversation between college girls and club girls. Turns out they are all virgins who never had sex before. Unlucky (or lucky) for protagonist he is caught eavesdropping. That is day they decide to silence protagonist by finally living up to rumors by making him there target of club.