大好きな兄に初めて彼女が出来た事にショックを受ける妹。妹は彼女に嫉妬し兄の携帯で勝手に彼女に「二股かけられてますよ」と言ったり「私という妹がいながら彼女作るなんて！」とか言い出してマジでイカれてる！でも酔わされて寝ているうちに妹が勝手に挿入して上に跨り腰を振っていて！なのにメッチャ気持ち良くて！
The younger sister is shocked that her beloved older brother has gotten a girlfriend for the first time. She's jealous of her and secretly tells her brother on his phone that he's cheating on her and says things like, "How dare he get a girlfriend when he has a sister like me!" She's totally crazy! But then, while he's drunk and asleep, his sister secretly inserts herself into him, straddles him, and starts thrusting her hips! And yet, it feels so good!

– JavGG.net