A little sister is shocked that her beloved brother has his first girlfriend. She is jealous of her girlfriend and tries to send her a LINE message on her brother's phone without his permission, saying things like, "How dare you get a girlfriend when you have a little sister like me!" It's really crazy! But while she was drunk and asleep, her little sister inserted herself without permission and straddled her on top and shook her hips! But it felt so good!