Underwear for hot weather

I went merino wool and have been very happy with the result over synthetic.

Previous to that, I got some 40% zinc diaper rash cream and would pretreat problem areas. This worked, but since switching to Smart Wool underwear, I don't seem to experience the problem. Even if wool doesn't solve your issue, its ability to be worn for days without smelling is worth the high price tag.

I like the Terramar mesh boxer briefs. I also have a pair of merino wool ones that work well but I feel hotter in those. The mesh ones are super light and breathable (it's all comfy mesh) and cheaper than merino. I've tried Exoffucio boxer briefs too but I still prefer the Terramar.

I think the most important thing is to go with boxer briefs with decent length. Too short and they will ride up and chafe I find. Having them tight down through mid thigh has resulted in no rash or irritation for me. YMMV.

I tried under armour. I find the cheapest thinnest synth tight shorts from Uniqlo breath better and are much cooler as well. Don't know if they have the same outside of Japan though, but it might be worth taking a look there.

i found that the UA heatgear boxer brief, espcecially the mesh version is perfect for your application, but as with many products what works for one person doesn't always work for others. my experince with merino is that it can hold too much moisture.

https://www.underarmour.com/en-us/mens-ua-mesh-9-inch-boxerjock-boxer-briefs/pid1228448

they are typically on sale at one place or another for around $15.

Ibex merino,boxer briefs work,great for me. They come in two,wrights and I like the heavier better, regardless of the heat. Expensive, but they last and I think you can find them on sale for about $30 if you look.

Have fun!

Are you saying that you have underwear that covers over the rubbing skin areas yet you still get the rash?

I like ExOfficio Give 'n Go boxer Briefs but…

Since you've already tried "long" drawers, have you considered using something like Body Glide on you inner thigh?

If you have contact without shorts, you will have more contact With shorts.

Just for fun, try some briefs. Sometimes keep the 'junk' out of the way helps.

I generally prefer boxers but if it's really hot I'll switch to boxer briefs. Always merino. Until last year it was Ibex but then I tested a pair from Woolx for BackpackGearTest.org and liked them too.

Which sucks.

http://www.webmd.boots.com/skin-problems-and-treatments/guide/prickly-heat-rash

This sounds like chafing to me. If it is, regardless of underwear, I use chamois butt'r to prevent it in the sensitive areas. Body glide's stick doesn't quit get into the areas I need it and Vaseline works and is cheap but stains clothing.