Tenkôsei (1982)

She’s slim, early 20s maybe, dark hair cut short, barely any curves — looks younger than she probably is. Starts off jerking the guy in a parking lot, both standing, his pants halfway down, her hand moving fast while he leans against a car. They go from there to a classroom, shirtless, her on top riding him slow on a desk, then switch to doggy against the wall when it gets rougher. Later scene shows just her alone in what looks like a bedroom, close-up on her face, mouth open like she’s talking or moaning, camera tight. Most of the action is medium or close, lighting’s flat but clear, no shaky cam. The school part stands out — real desks, whiteboard in the back, feels like they didn’t bother locking the door.