My older sister, Natsuho, has always been gloomy and shy, never making friends or working a part-time job, and spending most of her time holed up in her room. One day, while feeling frustrated and frustrated with her, I suddenly wondered what she was doing in her room, and sneaked a peek through the crack in the door. There, I saw my sister drawing a picture using my own naked body as a model. I was captivated by her surprisingly sexy body, which I thought was plain, and ended up masturbating. Later, while I was sleeping, I suddenly felt something good in my lower body... I opened my eyes and saw my older sister sucking my dick!? After I came, she was still muttering something, which made me feel disgusted, and then she even came into the bath! My sister's sexual curiosity had been awakened, and I reached my limit...