俺の妹が最高のオカズだった (フランス書院eブックス) (Associated Names)

My own sister saw me masturbating in a younger sister erot*c game. My younger sister, who always has a straight face, then somehow decided to help me masturbate. …… She made my friends wank and even got the most beautiful girl in school to get involved. Can I ever get a girlfriend now that I…