Hen (1997)

Two explorations of the Lolita complex. Sushiaki Karasawa, a young teacher at a Tokyo high school, becomes infatuated with Yoshida Chizuru, a 19-year-old student who appears in a shampoo commercial. She realizes he's attracted to her, so she shows up at his apartment and offers to sleep over. Soon he realizes that the games she plays have just begun. Later, Chizuru meets the new neighbor of her rock star boyfriend, Hiroyuki. The girl is Azumi Yamada, an innocent from the provinces who enrolls in Chizuru's school. This time it's Chizuru who's infatuated. What will Hiroyuki do when he finds out he's being thrown over for Azumi? Can Chizuru save her from Hiroyuki's revenge?