3DSVR-1882 - [VR] [8K] As the older brother, I took responsibility for developing the younger sister who couldn't cum from sex with her boyfriend to the point where she reached convulsive climax.

My rebellious younger sister seemed to be worried about something. Even though I was annoyed, I heard that sex with my first boyfriend didn't go well. My younger sister is crying, saying that she might be rejected if she continues like this, so I, as the older brother, should take a step back! "Huh? With a fucking big brother? What are you talking about? You're disgusting." At first, the younger sister didn't like it, but for the sake of her boyfriend, she seemed to want him to tell her something. There are some cute parts. This is what is called a tsundere. I don't have a lot of experience, but I was kind of horny with my younger sister's growing body, and being able to develop her body was a great way to kill two birds with one stone! ! I'll teach you everything from how to kiss to the climax of convulsions! !