Sakura works as a music teacher. She comes from a very rich family with very conservative parents who would go so far to protect their image, they even denied her to be with a man. As such she fills very trapped and sexually repressed, even pretending her recorder was a penis. She can fill shame for actions on occasions. She loves to give fellatio.
After Takeshi saw her treating her recorder as a penis, she made him keep what he saw a secret if she see and play with his own penis. Sakura lost her virginity to Takeshi and would explore and learn sexual acts through him.