GVG-445 Older sister's real sex education Yuuna Himekawa

Recently, my younger brother has started looking at my father's erotic books and watching my mother masturbate. - Yuuna, the older sister, can't see this and warns him, but she ends up sympathizing with him because of all the wrong knowledge about sex. - She shyly spreads her genitals and begins teaching her younger brother, who seems to be asking anyone about masturbation and sex, saying, ``It's really just a secret between the two of us.''