Three days without parents, when their tsundere sister hates her older brother's super-strong dick, she is making her cum over and over again.

Riko★A female student, stepbrother★A plain NEET man...The two of them suddenly end up living in the same house under the same roof due to their parents' remarriage. Riko, the dull brother who suddenly ends up living with him, is shocked. During the three days of a couple's trip, Riko is secretly filmed as she masturbates in the room with a vibrator she had hidden, and is forced to have sex. However, there was an unexpected match between the two...Riko's brother's sex compatibility was really the best. Her rebellious tsundere sister gets made to cum by her brother-in-law, whom she hates!