Peeping in a Girl's Dormitory (2000)

Tina Krause, who’s a teacher or something, leads Misty Mundae and Ruby LaRocca into their new flat, which looks like a house outside and like a basement inside. She gives them very strict rules : no smoking of any kind, no homosexual activity, well, everything that any good teacher would ask of her students in real life. Of course, as soon as she leaves, Misty and Ruby smoke a joint then proceed to make out on the bed. But, you see, Tina just pretended she left. So, after watching them for a while, she bursts on the scene and, in order to teach them the errors of their ways, forces them to disrobe then to take a bath and make out some more while she watches again.