Street Girls (1975)

The blonde’s on her knees first, bent over the back of a couch in a dim living room, getting pounded from behind. She’s slim with straight hair, wearing nothing, and you can hear the slap of skin as the guy — thick build, curly brown hair, mustache — grips her hips hard. Camera stays tight, medium shots that don’t flinch from the grinding motion or how far she arches back. Later she switches to riding him face-to-face on the couch, slowing down to grind in full view — you see everything. The mature redhead shows up later, purple-tinted curly hair, curvy with some age on her, entering the building outside before joining the action unseen. No full threeway shown in frames, but the vibe’s raw, unpolished, like something shot in a real apartment with minimal lighting.