I'm looking for the name of a doujin i read a long time ago. The content was quite similar to Zuko! Maman Ko, the difference being, as far as i remember, that the son didn't join in on the sex.
The content was a mother/milf in the bath, the sons friends come in and they have sex and at the end the friends hide in the bathtup so the son doesn't notice them.
I hope you can help me
[蛙子丁字] ゾクッ! ママン子 (コミックマグナム Vol.43)
or in english
[Kawazuko Chouji] Zoku!! Maman Ko (Comic Magnum Vol. 43)