GVG-578 Older sister's real sex education Hibiki Otsuki

Hibiki lives with her younger brother and father. - Hibiki, who cares for her younger brother, warns her father, who is an AV enthusiast, ``What will you do if your younger brother sees this?'' - But one day, the younger brother accidentally watches his father's pornographic video. - The younger brother misunderstands that sex is something scary and cries to Hibiki. - In order to correct her younger brother's sexual knowledge, Hibiki uses her own body to teach him about real sex...