Teufelscamp der verlorenen Frauen (1978)

One of the girls has that messy shoulder-length blonde hair and a curvy build — she’s the first to get fucked, flat on her back in a dim bedroom. Guy’s on top, grinding deep, balls slapping with every thrust. Camera stays tight so you don’t miss the face she pulls when he really starts pounding her. Later, second blonde gets bent over near an outdoor doorway, ass in the air, taking it from behind in doggy. He’s got a solid grip on her hips, slamming her hard while the jungle surrounds them. Final scene’s a handjob on a motorcycle — she’s jerking him off, then swaps to a blowjob with that mouth wide open. Sunlight, sweat, thick thighs, natural lighting — it’s all there. Guy’s got hairy arms and a rough look, fits the biker vibe.