Bouncing Buns (1983)

So this dude’s just chilling, jerking off in what looks like his bedroom—close-up shots of his hand working his cock, pretty basic but the lighting’s decent. Then the scene switches to a bedroom where a slim blonde with long wavy hair and tattoos is bent over the bed, ass up, getting ready for doggy. She’s got a tight, toned body and a nice round butt that’s the main focus here. Another chick’s there too, standing near the bed, just watching or maybe waiting her turn—she’s got a similar look, blonde, slim, but no tatts visible. The guy eventually joins in, and the blonde on the bed gets pounded hard from behind, her tits bouncing with every thrust. The camera work’s solid, lots of close-ups on the ass and the action, so you get a good view of everything. No crazy plot, just straight-up fucking with a side of voyeurism.