Last night when I was chatting with some friends online (we can talk with people and they can hear our voice.) and it was a bit late so I decided to leave the chat room, one reason was that my mom was asleep. So I said I needed to leave and I also told them the reason:
I don't want to disturb my mom's sleeping.
Then an Australian-Chinese (native speaker) said it's wrong to say that but he didn't tell me the right way. I wonder if it's unidiomatic to say that.