Associated Names:
Night with My Mother and Sister
My Mom and Sister
Моя мама, моя сестра
Это твоя Мама или Сестра?
童顏繼母
엄마야 누나야

Synopsis:
The sweet scent of my mother’s embrace, just like 3 years ago. I was lying on the same bed with my mom like when I was young, but she began to see me as a man… ‘I can give you everything, my son’.

https://lunarscan.org/series/is-it-your-mother-or-sister/

RAW: https://www.toptoon.net/comic/epList/81092/GC

I recommend reading the manhwa on PC using Yomikiru, and on Android using TachiyomiSY.

Does the mom or sister screw any other guy besides mc?

Base +9

As of ch32, no, the mom hasn't been screwing anyone else, even during the 3 years mc was gone. It's leaning that way for the sister as well.

Base +6, Gabaw +6, glitcher998 +9