Goutokuji Mina

Daughter of a celebrity madam, a real sheltered girl.

She is a deeply withdrawn daughter who has never even spoken to a man. The hero comes to the house as the madam's tutor and misses her very much.
Then, when she sees the madam and the hero having an affair, she says, "I want to learn that too," and she has him teach her not only to dance but also sex.