Said In Context: A more appropriate alternative to [sic]?

I'm a fan of as it were and in the vernacular for these purposes.

You would definitely not use sic, which is

used in brackets after a copied or quoted word that appears odd or erroneous to show that the word is quoted exactly as it stands in the original [Webster's]

When you are writing your own words, you are not quoting anything, and there is no original apart from what is on the page or screen you are using to compose your words.

Now, your stated intention is

... to say something fairly un-PC, using a deliberately anachronistic and inappropriate term, purely for effect.

The truth? There isn't going to be any word you could use to distance yourself from the effect of your own use of language in this case, nothing that is going to excuse your behavior in the eyes of people who are going to be offended by it. My advice is to either man up and take the heat if you really feel a need to express yourself in this way, or else leave that section out. And unless you're truly prepared to alienate people, the latter choice is the smart one.

Not sure if this really fills the bill, but if you're saying something unusual and want to draw attention to the fact that you're speaking metaphorically, adding "so to speak" on the end might be a way to go:

It was like french-kissing your cousin's hairy armpit... so to speak.

You can also use scare quotes ("…") in some of those contexts — to distance yourself from the thing within quotation marks. (This runs the risk of being misinterpreted as a direct quotation, but you can probably live with that.)

Your sentence, in the form

…that David Cameron isn't apparently keen on starting wars and sticking-it to some "fuzzy wuzzies".

would make it clear that "fuzzy wuzzies" is not "your" word, and something that may conceivably be spoken by someone of Cameron's way of thinking.