BAGR-025 Kokoro Ayase, the bitch sister who distorts the friendship and sexuality of her otaku brother

An otaku male college student who started living on his own after going to college. My sister, who was jealous of such a man, began to frequently go in and out of her brother's room. My sister negotiates with her boyfriend to rent a room for her to have sex with, but he refuses because she has a friend coming over. The troubled sister decides to carry out a diabolical idea that suddenly comes to her mind... A habit called Sado that he discovered while pushing his brother mentally. He laughs at his older brother, who has had their friendship destroyed and turned into a masochist.