[50,000 sales! From the super popular doujin circle Chinjao Musume.] A big family with a female student sister who takes the place of the mother. One night, unable to bear the sight of her brothers fighting over her panties, the sister becomes their pornographic magazine. Since then, the brothers have started treating her body as a convenient sex toy... and even lose their virginity!? They all flock together to use her as wank material. The father finds out, but the whole family starts doing it... A nostalgic erotic story from a time when it was hard to find material to wank every night.