I'm a little suspicious--that story is too pat and too lucid for a common metaphor. Usually you get several alternative origin stories, none of 'em quite right.

I went on a search for "mustardeer", and didn't encounter any authoritative definitions. The word shows up on the net a lot as a username/handle, and in the name of a ketchup company, and generally in random ways...but I didn't find any straightforward definition, and the wikipedia article on mustard never mentioned a "mustardeer" involved in the production of mustard.

So I'm leaning toward judging the term "mustardeer" apocryphal, and probably stories like the one from urbandictionary that are based on it are flights of fancy too.

I like etymology, too, because there's always a little mystery to solve when you start digging into words.

BTW, at urbandictionary I searched on the variation "cut the mustard", got that one first, plus several more. This one seems to be a derivative of the phrase (and the other results were irrelevant):

2. cut the mustard

Men who are unable to "cut the mustard" can more than compensate by simply LICKING THE LID.

She: What's the matter, Mr. Softee? Can't cut the mustard?

He: Don't worry, I'll just lick the lid instead.

She: Oooh, you lover boy, you!

tags: cut the mustard cunnilingus erectile disfunction penile add impotence

by Hugh Chardon Junior Jul 4, 2010

That's more like what I expected from urbandictionary.com.