Homeroom Affairs(1994)

Tanin no Kankei

The person waiting for Tokirou Ehara, newly appointed English teacher at famed Mitsuba Girls High School (and, incidentally, still a virgin), is Miyako Hase, whose pure and innocent face hides her "playful" nature! When he accidentally finds out her secret, Tokirou marshals his pride as a teacher and plots to make Miyako a proper student - but gets wrapped up in her cute charm instead.

(Source: Star Anime Enterprises)