Die heisse Liebe Eines Sommers (1981)

A slim blonde with short hair and a tight body is getting pounded by a dark-haired, muscular black guy in bed. They start off spooning, then she rolls on top and rides him hard, her small tits bouncing as she grinds down. Later it cuts to outdoors near a rocky shoreline — same blonde now naked with two white guys, one young blond doing push-ups nearby, the other older with gray hair just watching. The younger guy joins her in a three-way, all fucking in natural light with trees and water in the background. The camera stays wide during the outdoor scenes, showing full bodies and natural movement. The contrast between the dim bedroom intimacy and the bright, exposed outdoor sex is the main vibe shift.