The Velvet Edge (1981)

Sergio has organized a group sex party during which one woman is hooked up to a thrusting vibrator and another experiences anal sex against her will. Sergio tells the story of his grandfather in the 1930's and what amounts to two Bonnie's and two Clyde's who discover each other in a holdup and merge forces. In the process though, they are temporarily enjoying an idyllic love life in the backwoods. But one of them irritates a Mexican who shoots up the guys and beats the females.