DAYD-010 My sister tells me to teach me how to study. 7 days like a dream until I have sex with such a younger sister. Yu Aoba

One day, I was asked by my sister Yu to teach me what kind of wind it was. I thought I had been in contact with Yu for a while, but for a moment I was almost fainted by the bulge of my chest peeking from Yu's defenseless chest ... Yes, I was lustful for my sister Yu! Though I think it shouldn't be done. And then the dreamlike seven days began ...