Is the phrase "I just sucked it out of my thumb" used in American English?

I was born and raised in South Africa. We frequently used the term "to suck out of one's thumb", implying that an answer was just a wild guess or the notion had no evidence but was rather just surmised. At best it was the product of a personal thought experiment.

Is the phrase used elsewhere? I live in the USA and almost never hear it. Do Americans understand it? Can they figure it out or will they conjure up graphic literal images of my thumb in my mouth?

We have a vulgar version here in the US: "He pulled that answer out of his ass!"

A more innocuous version is "She pulled that answer out of thin air."

I have never heard the thumb expression.

That's interesting. This phrase, translated almost word-for-word (with simply finger instead of more specific thumb), is used in Russian, I wonder whether this fact has something to do with USSR—Africa relations…

In Russian it means not exactly wild guess, but that someone is trying to prove something and he doesn't have any really good arguments.

Also, seems that it is used in Hebrew. I don't know Hebrew, but I found this page.

It's a widely used expression in Dutch . Never heard it in English before, but it doesn't suprise me to hear it in South-Africa, given that much of the language there is strongly influenced by the Dutch that migrated there.