The eldest sister's real-life flexible education Cheng Haili GVG-078

Tetsuo, the father of the Shirokai family, is a strict father who rigorously raises his daughter Rei and son Ma-kun. One day, Ma-kun is caught by his parents looking at pornographic books borrowed from a friend. Resentful of his father's rudeness, Ma-kun, feeling sorry for Rei, decides to use her own body to teach him about sex…