Starting Now, I'mma Break Imouto Fair And Square.

I'mma wreck little sister like XXX., is the intent of this story.
She shares the name of an iconic imouto from that X-rated 1980s anime.

Two mangas are included:
"Ima, imouto ga shiyou-chuu desu" (Little sister is currently in use)16 pages
"Imouto A nikki / Shuushou" (Little sister A diary / Final chapter) (DL exclusive) 10 pages

The private stalls of the boy's toilet at school. In one of them, a girl is naked and bound.
The door is closed but the lock is unhinged.
Her brother is the one who bound her. Who stole her clothes and abandoned her, too.
Little sister sits here neglected, immobile between tightly corded hemp and porcelain,
hearing the voices of students come and go, feeling a strange tingle in her pelvis...