Forbidden (1976)

Starts with a guy in a suit holding what looks like a remote or toy, giving that “we’re about to get wild” look. Then it jumps to a hot tub scene with four people — two slim brunettes, one blonde with long wavy hair, and two white dudes in their 20s. One girl’s on her knees blowing a guy while the others make out and grope each other. The water’s splashing, and you can see her tattoo pretty clear. Next, the brunette’s bent over the bathroom sink getting pounded from behind — mirror’s right there so you see everything. The guy’s got a solid grip on her hips, and she’s really into it. Then they move to the bed, missionary style, and the camera gets up close for the penetration shots. Last shot’s the guy in a beige coat jerking off in the hallway, looking straight at the camera. Lighting’s dim but clear enough to see all the action without missing details.