A mother with sexual fetishes that are even more unbearable than a girlfriend; erections causing penile pain. Anzai Aijie DASS-579

Sakai and Kokoro are a couple. One day, when Sakai goes to her house, he encounters her mother, Aiyu, who has a large bust, and becomes very excited. When Sakai uses her bathroom, he sees Aiyu pretending to be Kokoro masturbating. He gets so excited that he gets an erection and masturbates, but Aiyu orgasms before him, causing him indigestion. Sakai can't forget this incident and begins to pursue Aiyu…