Ikan♂Chikan: Hentai darake no Manin Densha

Synopsis

Mao loves his childhood friend, Riku. Even after becoming a university student, he commutes from home so he can be close to him. But he has a secret... every day, he's being groped on the train to school! He struggles as he's violated from behind, but his body secretly likes it... Who in the world will save Mao from this train of sexual desire?!