My older sister, Kaho, who has been introverted and shy since she was a child, doesn't make friends or work part-time, and spends almost all her time locked in her room. One day, I had a vague dissatisfaction with such a sister, and I suddenly wondered what she was doing in her room, so I peeked through the crack in the door. What I saw there was my sister drawing a picture using my naked body as a model. I was captivated by my sister's unexpectedly erotic body, which I thought was plain, and ended up masturbating. After that, while I was sleeping, my lower body felt strangely good... When I opened my eyes, my sister was sucking my dick!? Even after I came, she was muttering something and looking disgusted, so she even came into the bath with me! I reached the limit of my patience with my sister, who had awakened to erotic curiosity...
