Aneki no Ero Aka Mitsuketara

"You know... you really piss me off."
"You're always sneaking away from trouble, always doing your parents' bidding."
"Are you like that at school?"
"I don't care about you, sister..." "Kick me."
"Don't talk back to me."
"You can't do anything on your own, you stupid little shit."
"You should be kicked like a bitch!"

The younger brother is abused by his abusive older sister. However, the younger brother had 'identified' an erotic selfie account on a certain social networking site.... He said, "This...is...my...sister...right?" The expression on his sister's face as she looked at the screen of her phone showed that the unmistakable image on the screen was unmistakably her own. The pornographic dirt, which should never be exposed, had been exposed to the person who should never be exposed. The oppressed brother strikes back...

(Source: Fanza, translated)

Note: A live-action AV adaptation (EBWH-014) was released on August 11th, 2023.