Four Play (1977)

Steve and Linda need a new idea for their latest film, so they toss around a number of ideas: how about a naive young virgin being romanced and seduced by an older man; or an attractive woman who's attracted to her old and senile husban's young chauffeur; or the gangster who tricks his boss' gold-digging wife into going to bed with him for free (she got screwed in two different ways); or the guy who sleeps with his friends' wife the gets her to pretend she's someone else for her blindfolded husband; or the school teacher who lives with a hillbilly couple and convinces the superstitous girl that he can change her into a mare with his special "magic". Steve and Linda consider the possibilities (in between their own passionate sex out in the rain, in a stream, on waterskis, anywhere they can manage to do it!