This came about as a snide joke by Dr. Tom. I was nitpicking a matter of measuring distances by the Pythagorean Theorem as is my wont. As it was tedious and pointless, I joked that my next meta would be about .... and ....; two things cliched for being intensely unpleasant. Dr. Tom suggested the I'd title it this. Sleeping on it, I realized Damn it, I am going to make this meta, aren't I? And I was right. The meta found itself, as per absolutely no-one's desires, being made.
I guess it's time for nuges:
There are two different mechanisms: one for each fine letter word
One metanism is related to ROOT CANAL and the other is related to COLONOSCOPY
Finding the five themers for ROOT CANAL should be pretty obvious. The five themers for COLONOSCOPY are meant to be hidden or hard to find but their existence is not as obvious as the ones for ROOT CANAL
So finding the five themers for ROOT CANALS have to do with canals....
And the five themers for COLONOSCOPY have to do with ... Colons... Ya know, the punctuation
Perhaps not the most important nudge but the themers are all in the DOWN entries ... because the title is DOWN my throat or UP my ###
So the entries that are canals have the etymology of the name of the canal as the main part of the clue Get it? The root of the name of the Canal.... And they have in parenthesis as description of the canal. I wasn't going to do this and they are really part of the mechanism and actually are a bit distracting, but I figure the grid itself would be too hard if it were just the obscure etymology and .... there is also an irrelevant seeming number
What's the deal with the numbers? Well, I am talking about ROOT canals
Okay, that should get you the first five letter word... Now what about the second word that comes from an entirely different metanism and the COLONOSCOPY part?
There are five clues with colons. (Sometimes they are a bit stretched. And there are some non-metanism clues that should have colons but don't as the colon clues are all hints to themers)
Oh, I guess I should mention this is one where hints in the clues do not refer to those entries at all but... they do refer to other parts of the grid
Anyway, clues with colons... anything notable about those clues
Something grammatical or spelling that is unnecessary but consistently done in all five clues
Something at the end of the clues?
Okay, what to do with those?
The theme is crawling up ones ###. You have five things. Five five instances were the things crawling up ###es. (You are welcome for the image.)
Now collect those ###es