Forbidden Encounters (1987)

A brother in love with his sister dreads the moment she will be leaving home, because she's getting married. The mother tells her beloved daughter about marital duty and demonstrates her talent at it when her husband pops in. Love between father and mother? OK that's the norm, yet the son is hidden under his parents' bed while they are at it. Then Uncle Adrien. shows how attracted he feels towards Lulu, the maid. Madeleine, a friend of the family has it off with Julien. Roberto Malone, J-P Armand and Michaelle Anders are in a sex club while a stripper is doing her act. This is followed by an orgy in the club. Julien mistakes his mother for Madeleine and fucks her without seeing her face. Then Julien makes it in a car with his sister while watched by a peeping-Tom. Then he has a go at the maid soon followed by Hortense, another of his parents' friends. Her husband happily joins in and we get a threesome. Julien makes it again with his sister in the sex club and she is joined in the toilet by Madeleine who teaches her how to make some easy money by sucking men through holes in the wall. Uncle Adrien, his brother (J-P Armand) and the Roberto Malone character take care of a woman in the club and the film ends on Geneviève finally doing it with her husband who had been too impressed by her to be able to really do justice to her beauty.