Biologie! (1990)

One of the guys has messy brown curly hair and a lean build — he’s alone at first, sitting by a window in an apartment with plants around, slowly jerking off with medium close-ups on his face and hand movement. Later he’s in an office with another slim white guy in his 30s, this one with short brown hair and a slightly receding hairline, both dressed casually. They start dry-humping against a desk, then one bends over while the other fucks him from behind, good rear-angle shots showing full penetration and the way the guy grips the desk. After that, the top gets on his knees and the bottom rides him in a reverse cowboy position, leaning forward with his hands on the other guy’s chest. The lighting stays flat and artificial, like office fluorescents, which gives it a raw, unfiltered look. Camera stays mostly at medium distance — no extreme close-ups, but you see the full bodies and how they move together.