@Dad_Aint_Hip I was hiking on the AT a few winters ago, in Va, Tar Jacket Ridge, to the Seely-Woodworth shelter, when my butt started getting cold, just around my belt area.
Turns out my bladder had sprung a leak and was filtering south towards my butt. Winter, snow on the ground, I was fairly alarmed! lol
Took the bladder out of my pack, couldn't use it anyway as the hose was frozen.
I was very worried. But...it turns out, with all my huffing and puffing along, and some miracle of wicking layers, my rear area just about dried up...Hallelujah and praise the hiking gods!
trivia story: did you know that St Bernard (of St Bernard dogs fame) is the patron saint of 'those who travel in the mountains, and St Christopher is patron saint of those who 'travel on foot'. At the gift shop of the monastery at the Grand St Bernard pass in the Alps, I found a little medallion with St B on one side and St Chris on the other! I would wear it backpacking, but it's too heavy (that's a joke)
ps oops almost forgot, that bladder was fired from the first team and relegated to backup status in the garage for punishment.