Bakunyû fuzoku: Okini mesumama (2000)

Fuyusako lives with her half-brother Natsuo. She secretly works at an image club without telling him, and Yumihiko, a regular customer at the image club, is Fuyusako's half-brother. To Natsuo, Fuyusako was like a virgin, and that was the reason why even if she had a lover with him, it wouldn't last long. Fuyusako takes the plunge and confesses her truth for the sake of her younger brother. However, after Natsuo cleansed his dirty body, he embraced Fuyusako. One day, an incident occurs where Fuyusako is raped by a customer...