Score (1974)

Liberated '70s couple seduce another couple into experimentation with bisexuality and group-sex. In the mythical European city of Leisure, married couple Jack and Elvira have an ongoing bet regarding who can seduce whom. This comes up in the wake of a swinging night with a couple of tourists picked up via a newspaper ad. Elvira, a self-professed “sexual snob” has bet she can seduce newlywed Betsy, married to handsome marine biologist Eddie. If she fails by a certain midnight, then Jack gets to seduce Eddie. While Jack and Eddie go to work separately, Betsy comes round to visit her new friend Elvira. She’s very intrigued by Elvira’s open admission of her swinging lifestyle, including spouse-swapping and drugs