During her three years of study, a busty student was irresistibly trained to submissively masturbate. (Yuzaki Karen, PPPE-223)

A teacher with a twisted mind uses pitifulness as a target, forcing her to urinate during exams but preventing her from going to the toilet, causing her to lose control of her bladder. To turn her into his personal sex toy, he takes the training further. He brings her to orgasm with a remote-controlled vibrator in the hallways and stairwells. He ejaculates in places where she's studying. He writes everything on her entire body. Having been trained to be like a sex toy, pitiful girl gradually begins to feel like a slave…