Confessions of a Young American Housewife (1975) on Netflix

An attractive but conservative mid-30's housewife stays at the house of her sexually open daughter and soon becomes involved in her daughter's swinger lifestyle.

Young, happily-married New Yorker Carole enjoys being part of a swinging foursome with her husband Eddie and their friend-couple Anna and Pete. This serves to keep things interesting. One day her widowed mother Jennifer comes to stay in their house, but she is more on the conservative side and doesn't know about her partner-swapping daughter. Soon she herself kicks over the traces and starts to enjoy the favors of both male and female bed-mates.

Carole, a beautiful young happily-married woman, lives in New York with her husband and enjoys a wonderful sex life. Things just could not get better. That is until her mother comes to stay with her and emotions from their torrid past come back to her. What follows can only be described as a sheer orgy of seduction and eroticism.

—Ørnås