Teru, the younger brother who became interested in sex after hearing about it from a friend. Then, Teru would blurt out 'sex, sex' even during meals with his family, making his sister Yuzu, who is around the same age, feel awkward. Yuzu tried to teach Teru about sex by gently guiding him to ejaculation with her own hands, but this only fueled Teru's curiosity...
