GVG-544 Big Sister's Real Sex Education Haruka Namiki

Haruka, an older sister who loves her younger brother. However, one day, her younger brother starts to surprise her family by repeatedly saying "Let's have sex!" in front of her family. Her troubled Haruka looked into the cause, and she seemed to be affected by her younger brother's male friend having sex with her mother. Knowing that her younger brother was innocent about sex, Haruka decided to instill her correct sexual knowledge.