Tanaka

Tanaka is the homeroom teacher of Endou Aina, and describes the girl as bright and cheerful, but laments that she is often teasing and provoking him. He is surprised when Aina offers to 'pop his cherry' after she correctly guesses that he is a virgin. He states that he is more into mature women, and that her body is of no interest to him. Despite this, he is unable to resist Aina's sexual advances and ends up having sex with her. This in turn makes him consider himself to have failed as a teacher. Even though having sexual relations with Aina lead Tanaka to feel that he had failed as a teacher, Tanaka is still interested and willing to have further sexual relations with Aina.

(Source: Both the OVA and manga of Lovely Aina-chan)