Both Ends Burning (1987)

Amber Lynn and Buddy Love star as a married couple who like to spice up their sex lives with a healthy dose of swinging in this head spinner. As the flick opens, they're getting ready to welcome old college chums Sharon Mitchell and Jerry Butler for the weekend. Of course, the couples aren't as close as they once were and Amber and Buddy haven't yet told their old pals about their new swinging lifestyle. Sharon finds out about it on her own the first night, when she hears moaning coming from the next room and peeps in for a quick look. She's shocked to find Amber taking on someone other than her husband. Sharon confronts Amber the next morning, only to have Amber invite over her lusty gal pal Bionca to play. Sharon storms out in a huff, while Jerry decides to join right in by happily trysting with Bionca