H02144 Osananajimi to Doukyuusei Ep 1: Miyu's Train Trap

Miyu is groped by a molester on the train home, and her classmate Shun rescues her, then kisses her. He walks her home, teasing her about the incident, but the whole thing was a trap he set. That night her childhood friend Kou takes her virginity, and the next day Shun drugs her and trains her as a sex slave. Afterward she starts masturbating when she remembers, unsure if she liked it or wants more.