The Landlady (1990)

Starring: Hyapatia Lee, Madison, Tom Byron, Sunny McKay, Mike Horner, Patricia Kennedy, Heather Sinclair

Adam is a college student who invites his friend Scott with wife Carol to his new rented apartment. While Adam is in the bathroom, Scott and Carol conduct housewarming in Adam’s bed. Adam comes in and notices his buxom landlady Lily peeping from his door on Scott and Carol. Adam promises his landlady it won’t happen again, but later brings over his date Pat, who Carol set him up with. He doesn’t know that his landlady once again opens his door to peep. As soon as Pat leaves, his landlady takes her clothes off and invites him to her room. In the days that follow, Adam dumps Pat and neglects his studies. Scott comes to complain, but cheats on Carol when he too cannot resist the landlady’s seduction. Treating Adam like a dominatrix, his landlady involves him in a sex orgy that includes Pat. Once it’s done, Adam checks a secret door. The screen fades out as he stares in horror in what’s behind it.

Screencap