Infidélités (1975)

Starts with a tight shot of a slim brunette in her 20s bending over just enough to show her small tits while she goes down on a guy. You can see her tongue working the underside, slow at first then getting sloppier. Next scene she’s in a red robe handing something to a dude in the hall—looks like a toy, but the camera stays wide so you don’t get a clear look. Then she’s back in a light dress, standing over the same guy while he’s bent over; she’s either fingering him or prepping with a toy—hard to tell, but her hand’s definitely back there. Big payoff is the group shot: three girls in long skirts, one blonde, one brunette, one with dark hair, all around a guy who’s already getting head from the brunette while the blonde watches with a drink in hand. The third girl’s just standing there looking at the action. Finally cuts to a close-up of doggy style, her ass up, him pounding away—no faces, just the grind. Lighting’s warm and dim the whole time, feels like someone’s actual house.