Groper Train: Deep Inside (1999)

Yukiko is on a crowded train when a wireless vibrator is inserted into her and she moans quietly. The person operating it is Shinozuka, an assistant professor in her seminar. Ozawa, who has an obsession with the voices of women being molested, becomes interested in Yukiko and follows her. Yukiko is subjected to Shinozuka's violent assault in the university research lab. Ozawa takes a secret photo of Yukiko on the train and approaches her, promising to fight off the sexual harassment, but...