What does this expression mean? I heard it in a video where the person said something like
This sounds right, but in fact, son of a gun, or as my younger son would say, fudge knuckle, it goes wrong in the end.
I have never heard that expression before but it sounds like one of those nonsense expressions that are often used as a general exclamation. I would guess, too, that fudge is meant to be a euphemism for fuck, as such euphemisms are common in these nonsense phrases.