Theres a hentai by the name of otome dori. The plot follows some guy who likes this girl. But his little sister likes him. Turns out the little sister was in a rape ring of old men and she makes the old men rape the girl he likes. They film the encounter and send it to him in an effort to make the mc turn towards the little sister for romance. She gets raped a few times all the while our mc watches along the sidelines never doing anything to prevent it. It gets really sad as we see the girl he likes slowly go down the old man cock rabbit hole and slip into not wanting anything else aside from old fat cocks. Moral of the story is to not be a bitch boy and just to ask her out. If she declines then thats fine. At least you arent being a bitch getting cucked like katsuki.