The top student's older sister was precocious and had learned to masturbate early. The first time the sister made her younger brother lick her asshole was during the summer when she was in junior high and he was in elementary school... In the end, this habit continued even after he became an adult. Even if she had a boyfriend, her sister couldn't climax without anal cunnilingus on her brother and started demanding sex, venturing into forbidden territory... The ultimate body compatibility of siblings.
