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?
Best Answer
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.