About those boxer briefs. They can be both very comfortable and extremely uncomfortable. I've tried both kinds. Avoid cotton (especially thick cotton) and boxer briefs that stretch 2 - 4 inches down the leg. If your junk sweats that cotton will absorb it all and keep that area moist all day long. Wet skin chafes easier than dry skin. Short boxers on the other hand will ride up your leg during the hike and create this lovely bunch of fabric that grinds up your inner thighs. Ouch
You are better off with fast drying thin synthetic fabrics in either briefs or long thigh length boxers/boxer briefs. Briefs need to be tight or you will get the same problems as with the short boxers. It is up to the wearer if they prefer a tight fit or a loose fit in their long thigh length boxers/boxer briefs as long as they dry fast.
Whatever you get make sure it does not have seams in places you do not want to have seams. Seam areas are prime contenders for chafing.
Underwear matters.
You are better off with fast drying thin synthetic fabrics in either briefs or long thigh length boxers/boxer briefs. Briefs need to be tight or you will get the same problems as with the short boxers. It is up to the wearer if they prefer a tight fit or a loose fit in their long thigh length boxers/boxer briefs as long as they dry fast.
Whatever you get make sure it does not have seams in places you do not want to have seams. Seam areas are prime contenders for chafing.
Underwear matters.