I heard this the other day and had to share because I use it frequently.
“Don’t get your drawers in a wad.”
From the context, you may or may not be able to tell the word drawers is a shortened form of the word under-drawers. Down south, this is a gender neutral reference to undergarments. You might call them underwear, underthings, underpants, underclothes, or just plain undies.
Whatever you call them, try not to get them in a twist. That’s not fun for anyone.