Onna Jimuin: Shikijo Seikatsu (1982)
A librarian who is the mistress of of a married dude sleeps with a pregnant young woman and her lowlife boyfriend separately, and then she tries to break them apart.
Actors: Ayako Ota
Sex Hunter (1980)
A disabled guy’s sister who is in love with him trains his virginal girlfriend to become a sex-mad slut, hoping that when he sees what a whore she has become, he will reject her and fall straight into his sister’s loving arms instead.
Pleasure Campus: Secret Games (1980)
A husband pretends to be a robber and grapes his wife, but she willingly screws him after some initial resistance. To determine if she thought it’s him and just played along, he asks his friend to pretend as a robber and try to grape his wife to see if she’ll react the same.