Jutten!

Jutten! is about a boy who goes to his first day of high school, thinking itll be full of awesome (pervy) meetings with sexy girls and whatnot, but instead has a lot of bad luck and gets peed on by a dog–amongst other things. A girl who uses her bike to drive over his ass sorta helps him and gives him a handkerchief with a 10 yen coin in it (hence the the series title) and … very plausible stuff happens afterwards.