Chikoubo ~Kegasareta Souden~  

 恥肛母～穢された双臀～ 

Keiichi is a high school student. After his father, who was a man of money, passed away, his relatives crowd around him and his mother, Miyuki. Keiichi gives an advise to Miyuki to keep money only for living and waive other money. That's enough for Keiichi. Keiichi has been trying to sleep with Miyuki since his father's death and finally, he has a sex with Miyuki forcibly. One day, here comes Kyoko and she insists that Keiichi is her own son. She left Keiichi for unavoidable reasons and wants to get back Keiichi. Keiichi is so attracted by Kyoko and....