You'll Breathe Me In (You Won't Release)

His first driving lesson with Louis takes place on a Saturday.

Harry stumbles out through the front gate in thrown-on baggy jeans and his ratty Ramones shirt, sees Louis leaning casually against the car, and his knees nearly give out. Apparently "not another surly teacher" meant a drop dead gorgeous twenty-something scruffy guy with shaggy brown hair and cheekbones sharp enough to chop a salad with. Clearly, Robin's trying to get Harry killed at seventeen.

Or, the AU where Louis is a 25-year-old driving instructor and Harry is a 17-year-old virgin who's really awful at seduction, except for the time he gets Louis to fall for him and fuck him senseless and take him on kinky adventures.