The younger brother, who saw through such an older sister, invites him to sex for the first time in a long time to take a break from studying.
Unlike her younger brother, who is honest in her desires, her older sister tries to refuse, but she loses to her persistent younger brother and ends up deciding.

She is embarrassed to be made by her younger brother and can't be honest, but she confesses that she was actually greedy when questioned by
her younger brother. At first, the older sister refuses to kiss her, but at the end of the day, she actively entangles her tongue and obediently feels good