Shinjuku Mayonaka Monogatari: Otoko to Onna (1972)

Starts with this dude, average build, clean-shaven, looking relaxed on a bed. Next to him, two skinny Asian girls with long black hair—one’s curled up in a blanket, the other’s just smiling while he waves a condom wrapper like it’s no big deal. The shy one’s got this embarrassed look, but you can tell she’s into it. Later, they get down to business—nothing too wild, just solid fucking with good angles on the dude going at it while the girls take turns. The lighting’s warm, makes everything look cozy, like a small apartment or something. No crazy positions, just straightforward threesome action with a natural vibe.