Miiro, a serious girl of her age, was worried that she couldn't keep up with the sexual topics of her classmates. One day, I took the plunge and visited the teacher's home on a holiday to ask my homeroom physical education teacher to teach me about sex. However, the teacher is a genuine amorous teacher who goes to the customs every Sunday, and at first he was trying to drive back Miiro, who visited the teacher's home to go to the customs he had reserved, but because he was too persistent, he took advantage of her curiosity and played with her body in the process of development, and Miiro also took what the teacher said seriously and gradually trained her body as good as the teacher.