Les petits slips se déchaînent (1981)

Cathy, a brunette, and Lise, a blond beauty, decide to take a sailing training course. Lise seduces Nick, the comely sailor, but forsakes him as soon as she has attained her end.. Cathy sets about comforting the vexed sailor man. Back in Paris,she surprises his boyfriend's girlfriend making love with another man. She decides to teach him a lesson. All is well that ends well: all the protagonists join in an orgy! Written by Guy Bellinger