"Debauchery" (猟色) series from Nikkatsu.
Ryoko Watanabe is a bored housewife named Ami who throws herself into the “Madame Machiko Society Club” to spice up her marriage by making love to random men. This world of lust turns out to be kinkier than Ami thought it would be and may end up having a reverse effect on her precious marriage.
A female college student who would have ended up in an ordinary life, ordinary sex, and eventually an ordinary marriage is drawn into an unusual sexual experience by chance. She's a private tutor who intervenes between a son and his mother. This strange love triangle creates a skewed sexual relationship. Nikkatsu depicts the subtleties of female psychology, which sways subtly in such a perverted world.
