Eimi is a swimsuit model, she had a few days off so she decided to visit her parents at home. She also met Satoshi again, but it seems like he has something to confide. She asked and found out that because she is a swimsuit model, he often gets teased by friends and still doesn't have a girlfriend. In order to teach her younger brother about sex, Eimi planned to sit down and explain how to have sex to him, but her body and beauty made him unable to control himself. He pinned her down and forced her to "practice" with him...