Female Teacher (Secret) I'll Teach You(1979)

A high school student is infatuated with his beautiful tutor. This beautiful tutor, whose perversions are hidden from the outside world, is married to a sexual sadist who enjoys dominating partners and using bondage as a means of pleasure. The student who longs for his titor eventuslly discovers her secret and uses this knowledge as a means to coerce her into an illicit affair.