Jokyoshi Nikki 2 Abakareta Sei (1996)

Mari is a high school teacher who is earnest and somewhat cold. Tired of her monotonous days, she discovered a secret game: wandering around Roppongi at night and seducing men. She enjoys the pleasure of lewd acts with strangers and finds temporary peace. Her student Toshihiko, who happens to witness her nighttime appearance, is captivated by Mari's seductive figure before he knows it...