Fuzzy Lips.

Based on the adult manga by Inu, Fuzzy Lips is about a disaffected young woman named Katakura Kon who enters a forbidden and hyper sexual relationship with her homeroom teacher, Mr. Kurosawa. She rarely attends classes now and has taken to living with him but neither one is willing to express their feelings to each other. Frustration overflows and even when secretly dating, they can't quite communicate and connect unless they are having rampant steamy sex!