JUKF-067 My brother is my wank toy, Sato's little Noka

A girl named Noka, who is more interested in sex than studying, has a brother who is repeating his third year of college and often peeps at her masturbating or bringing her boyfriend home to have sex. One day, the perverted brother sneaks into Noka's room and fails in his night● attempt. From that day on, the power dynamics reverse, and the foolish brother starts being treated like a lapdog by his sister as part of his daily routine. Both are equally bad, but perhaps this brother and sister deserve each other.