Heisser als Lava (1978)

Starts with this slim blonde—navel piercing, long straight hair—grinding on some dude cowgirl style. He’s got tats up his arms, lying back like he’s letting her do all the work. She’s not just bouncing; she’s really rolling her hips, slow at first then faster, like she’s trying to get him off quick. Camera catches it all from the side, so you see her ass flexing and his dick disappearing inside her over and over. Then it cuts to two girls on a couch—one blonde, one brunette, both with shoulder-length waves—kissing and touching while the same guy stands there naked, just watching. They’re not fully undressed yet, but you can tell they’re into it, especially the way the brunette’s hand keeps sliding up the blonde’s thigh. Later, the blonde’s back on the bed, legs spread, and the guy’s face-deep in her pussy. Close-up shows her biting her lip, fingers gripping the sheets, so you know she’s feeling it. Lighting’s dim but warm, so everything looks soft but still clear—no weird shadows, just good angles on the action.