http://www.urbandictionary.com/define.php?term=check+your+neck

Can you remember ever having heard this expr before Jeff Foxworthy

No.

Nope. Never heard of it before. It appears to be only used in the US.

Not a US term either. Per research, comedian Jeff Foxworthy uses the phrase. ("You know you're a redneck if ..."). And you'll find it in sites about thyroid problems.

The phrase gets only 18,500 ghits, over 95% in one of those two contexts. If you seach for "check your neck" -foxworthy -thyroid you're down to 776 ghits. And these are things like "check your neck to feel if it is tight or sore"; on a quick scan of them I don't see a single one using the phrase as a term in context.

Nope

shu: By coincidence I also did minus Foxworthy and thyroid, and without performing a tedious search I agree it looks like the expr hasn't caught on yet

I've heard "Check your six" from ex-fighter pilots in reference to an enemy attacking from the six o-clock position (to the rear).

By the way, I did just check my neck, and it was not red - it was dirty. I washed it. I hope you're all pleased to know that.

Asa the only partly dirty old man

quote:

shu: I agree it looks like the expr hasn't caught on yet.

Which tells you something about the reliability of Urban Dictionary, which included it.

shu: Yes, but sometimes UD is a good source. Oftentimes they're first to pick up on a neologism for a quick check. Furthermore, several entries with a similar def, esp if they have a predominance of thumbs up, is a pretty reliable indicator