ママこんだん ～ママの秘密の懇談会～

Makoto was living happily with his mother.

One day, his classmate "Ken" told him that he was having sex with his mom, and said that other students who were interested were calling their mothers to school to have orgies.

He was shocked to hear this, but when he got home his teacher was there...
...and his mother seemed to be acting differently than usual...