My mother used to use a word which I have long suspected was Yiddish. It sounded to me like PUSH-mook, where mook rhymes with look. She would say "let me wash your push-mook" to a child, and would proceed to wash the area around the child's mouth. Children do have a way of getting that area messy while eating.
My mom wasn't Jewish, but she grew up with a lot of Jewish friends.
Today I saw that "pisk" can mean "mouth" in Yiddish, particularly in the sense of animal mouth or maw. In a slangy way, it is used for human mouths.
It must be said, my recollection of the pronunciation word is untrustworthy. And I suppose Yiddish sounds don't correspond exactly with English sounds anyway.
My attempts to figure this out are not helped by the fact that Yiddish is usually written using the Hebrew alphabet, which I do not know.
Mother, my mother dear,
I'd ask if you were still here.