My mom lets you do it, your mom lets me do it - Shinobu Igarashi, Yuriko Shiomi DTKM-029

This is the story of two mothers and their sons. The adopted brother is staying at his house because his house is being renovated. Although the son brought his girlfriend home, he can't forget his desire for his mother, regardless of how many times his girlfriend and mother have sex. After seeing this, a neighbor suggested that he come and exchange mothers for sex...