Eimi is a swimsuit model, and she got a few days off, so she decided to go home to visit her parents. She also met Satoshi again, but it seemed like he had something on his mind. When she asked, she learned that because she is a swimsuit model, he often gets teased by his friends and still doesn't have a girlfriend. To teach her younger brother what sex is, Eimi intended to sit down to explain how to make love to him, but Eimi's body and beauty made it hard for him to restrain himself. He pinned her down and made her 'practice' with him...