Imouto NTR♡ Incest: I peeked at the sex of my very sensitive, busty little sister, and I ended up having blood-related sex...

My classmate's friend is cool and popular with both studying and exercising, and although it's frustrating, she also has a girlfriend. I hear that she is adorable and has a very sensitive body. However, one day I saw my friend flirting with my sister! I can't believe she's a little girl!? Since then, I've been bothering me about my sister's body, but even after that, I can't keep up... Before I knew it, I had been charging into the bathroom where my sister is.