SONE-681 I was awful to my girlfriend's younger sister who said, I'm so innocent that I do what an older man says!? and secretly kept fucking me. Itoi Ruka

I decided to teach her younger sister, Ruka, how to study. Even though she is called a female student, she is still a child, innocent, and cute. She seems to have little knowledge about sex, and she shows off her panties without any protection, and shows through her legs... What's more, my breasts are also big for the year. Even though I know it's her sister, I see her as a 'woman'. When I realized it, I was young and soft