Ingyaku reijô: Suitsuku shita

Original title: 淫虐令嬢 吸いつく舌

Yuko and her son, Shogo, come from a family of doctors. However, Shogo is on the verge of failure in his medical career and takes out his frustrations on his girlfriend, Mao. Mao is passive about sex and can't even perform fellatio properly. One day, Shogo's cousin, Mikiko, shows up at his house.