Try finding a boxer that is NOT cotton. I do alot of backpacking & rock climbing in the summer and cotton is a killer. Find a synthetic fabric, like a polyester. Try an Under Armour product or something similiar. I know that they may be a bit more expensive but try it and you will never go back.

And you better believe that I backpack in my kilts!

Here are a few of my favorites:
http://www.underarmour.com/shop/mens...rt/1000668-001

http://www.underarmour.com/shop/mens...-T/1000084-600

http://www.underarmour.com/shop/mens...-T/1000039-400