NUKA-055 The next-of-a-kin mates are close.

Mother Rin's desire for sex, but his father is calm, so she always wants to be dissatisfied, and Ying is aware of her suffering, but he can't do anything as a son but pretend he can't see it, and when he sees Rin's masturbation, he's too lonely, so he decides to comfort her... That's the tenderness of Yingsuke, and Rin just thought he'd once accepted his son, but Ying has inherited the XUE of Rin's sex enthusiast, and has made Rin crazy...