Tsukushite Agechau 5 ~Motomeru Otome-tachi~

The protagonist attends an all-boys school and struggles with communicating with girls. After losing a bet, he infiltrates a girls' school with a camera. Caught and beaten by a guard, he's rescued by four dormitory girls who tend to his bruises. They kiss each other, claiming it's a greeting rather than lesbian affection. Desiring the same greeting, the protagonist soon finds himself in romantic entanglements with all four girls.