Female Teacher: More Lewdly (1997)

Original title: 女教師 もっと淫らに

Fumiko Matsuzawa (24), newly assigned to Fujioka High School—a den of delinquents—becomes prime prey for the students almost immediately upon her arrival. Male students hurl obscene remarks at the beautiful, voluptuous Fumiko. Little does she know that among them is Takaaki, the younger brother of her boyfriend, Motoaki. As usual, Takaaki and his delinquent friends roamed the streets looking for victims to gang rape, eventually targeting a younger student named Maki. Seeing her former self in Takaaki's self-deprecating attitude, the polar opposite of his elite older brother Motomasa, Fumiko began paying special attention to him. Though Takaaki verbally rejected her advances, sensing a familiar vibe, he gradually opened up to her. But when Takaki finally returned home after so long, what he saw was Fumiko and his beloved older brother, Motomasa, in each other's arms. Takaki cursed them with vile words.