A defenseless, busty sister gets fucked by her super-strong younger brother. She thought she was seducing her virgin brother, but... it turns out to be a surprise!

Nanami, an idol in Tokyo, returns home and hears from her mother that her younger brother is acting strange recently, so she asks her why directly, and when she asks her girl in her class makes fun of her for being a virgin. Her father asked her to cheer her up, so she lets her younger brother touch her breasts to teach her how good she is about girls... and she suddenly woke up to something and began to squeeze her completely erect cock and insert it raw into Nanami! After that, my younger brother chases me around me all the time, and I ask him to mate anywhere in the house...