I was holed up at home playing erotic games on my smartphone, but I noticed my younger sister's big breasts, and I wanted to someday practice on her what I had played in erotic games. One day, his parents decided to go on a trip for their wedding anniversary. When his chance arrives, he takes advantage of his sister's kind nature and succeeds in getting her to do what he says. At first, my younger sister didn't like it, but she seemed to like her nice things and gradually started responding to my requests, even though she was embarrassed...