Eden no sono (1980)

Starts with a guy in glasses sitting between two skinny Asian chicks with long black hair. One of them goes down on him right away, deep-throating while the other one plays with his chest. The camera gets tight on her lips sliding up and down, no gagging, just smooth. Later they move outside to a hot spring where the same girl is bent over in the water, taking it doggy style. The guy’s got a lean build but knows how to hold her hips and slam it in. Water splashes everywhere, and you can see her tits bouncing with every thrust. The whole thing has a chill, natural vibe—no over-the-top moaning, just real-looking chemistry.