My friend's wife is a lewd private tutor

Because of his son who is unable to study, his father decides to tutor his friend's wife, Marina. The son of an acquaintance is hoping for a beautiful and educated Marina, but she falls in love with Marina at first sight with her busty glasses, and she tries to use her skills to play with Marina's body with her own hands. Unable to see her acquaintance's son who doesn't concentrate on her studies, Marina aims to improve her academic ability using naughty lessons...