The Toy Box (1971)

 The Toy Box (1971)

The plot revolves around a swingers party, where the guests act 

out sexually perverse scenarios for a man called "Uncle" to obtain 

gifts from a mysterious "toy box." But when a couple of the guests 

suspect all is not as it seems, including the identity of "Uncle," 

we go from a very commonplace sexploitation piece and veer off into 

an insanely wild and absurd story involving aliens and humans sold 

as drugs. (IMDB)