Firebox (1986)

The blonde in the mohawk is topless early, standing by the bedroom door with tats on her arms — she’s lean, got a flat chest and a wild look. She joins the other two, both slim brunettes, one with short hair giving a blowjob on the bed while the guy lays back. They switch to doggy after that, one brunette taking deep strokes, her back arched, face reflected in a mirror across the room. The camera stays wide for most of it, giving full-body views during the side-by-side scenes where the guy fucks one while the other girl strokes him. Lighting is dim but clear enough to see facial expressions — all three are into it, no faking. The mirror shows double angles during penetration, especially during the long doggy sequence.