I first heard of Exofficio over on Expedition Portal.  I wish I had known about them years ago.  I'm a xxxl truck driver. Swamp ass is a real concern.  Cotton is rotten and has no business on your junk.  Seriously, these are great. Wear them for a couple days in the heat and there's no stink.  You can freaking wash them in a bathroom sink!

Joking aside these things are legit.  If you've not made the jump to synthetic draws you are doing yourself, and your junk,  a disservice.