Asuka and I are cheerful and lively brother and sister who love to tease each other. Recently, Asuka has been making fun of me whenever she finds out that I'm a virgin. Then one day, I finally got a girlfriend! Asuka was happy for me, but she gradually started to worry, saying, "You don't have any sexual experience, do you? If you're bad at it, she'll hate you," and suggested, "That's right! Why don't I teach you how to have sex?" I thought that was a bad idea, but I didn't want her to hate me, so I decided to give myself to Asuka...