Island Of Dr. Love (1979)

A slim brunette in glasses is sitting in a medical room with a guy in a cap, both looking like they’re playing doctor. She’s got curly dark hair and a tight body — you see her reading a magazine later in a waiting room, totally casual. The scene shifts to a bedroom where she’s sandwiched between a younger dark-haired guy and an older gray-haired guy with a cane. They take turns fucking her — one gives her a blowjob while the other rides her face, then she gets pounded in doggy from behind while the other jerks off watching. The older guy later dominates in an office setting, standing while she’s on her knees, face deep in his lap. Camera stays wide in most shots, no close-ups until the facial close-up of the younger guy, mouth open like he’s moaning hard.