About, is it tighteys or tidys?

I was reading a favorite blog yesterday, and in the post she mentioned some unmentionables of the boy kind. You know, Fruit of the Looms, Hanes, old-fashioned briefs. What's the other, more contemporary phrase going through your head right now (and are you seeing Tom Cruise dancing?)?
Well, I had to do a double-take and Google the little phrase, because what I read was different from what was in my head.
Tidy ... or tightey ... whiteys.
(Pick your spelling there, it's totally all over the place.
Well, in the blog, the author referred to the white briefs as tightey whiteys.
But I always thought people were saying, TIDY whiteys.
Well I'm a gotta-know kind of girl. So I hurriedly Googled the phrase and found the most exhaustive, interesting, and probably useless paper on that very subject, written by somebody at Stanford (of course).
Oh do take a minute and go read it here>
And in case you WON'T take a minute to go read it, here's the kind of thing you'd would have learned:
"There are (at least) two ways these arrays could come about. If the expressions have been around for a while, then an original tidy could have been being reanalyzed as tighty by people who thought tightness was more significant than cleanliness, so that tighty eventually overtook tidy. These things happen, and if you don't believe they do, you have another thing coming."
Imagine the phrase tightey/tidy whitey having an array!
And someone caring enough to write a whole paper about it.
Of course, I did a little first-hand research, of two whole people. I asked a 20-something and a 50-something. The 20 replied right way that it was "tightey." The 50 had to think a minute, then also picked the "tightey."
I stand corrected.
Do you remember the "pop vs. soda" conversation of some years ago? Turned out that was a regional thing. IT'S a whole study, too--go look here>
I wondered if the tightey/tidy thing was geographical, but now I think it's just some people have better ears than others!
Well, how 'bout you? Boxers or tightey/tidy whiteys?