I'm outdoors quite a bit. But the one thing that takes me out of action is sweat buildup and rubbing in my nether regions. It can literally take me out of action for a few days. I think it comes down to friction and sweat. I use performance boxers daily but it doesn't seem to help the situation. It does seem like hiking causes the majority of these problems.
That kind of problem is miserable, but fairly common. There are a few things I'd suggest to solve it.
Good, wicking underwear. It sounds like you've tried at least one version, but it is worth experimenting with different styles, brands and materials. I'm a fan of merino wool for dealing with sweat. I find it works as well as or better than any synthetic performance fabrics I've tried. Silk is another natural fabric that might help with chafing.
Anti-chafe cream. Body Glide is the brand I'm familiar with, but there are many others. It acts as a slick layer on your skin to reduce rubbing.
Weight loss. Obviously, this isn't available to people who are already thin, but if extra fat is causing or exacerbating the rubbing, weight loss will help. A much longer term solution than the other two.
good ideas Karen. others:
- hike in shorts even if it is cold. Thin nylon pants instead of heavy cotton jeans. Consider a Utili-Kilt which are completely open and ventilated. Your legs generate a lot of muscle heat while hiking and really don't need much insulation
- compression shorts as a concept are all about holding in place and preventing movement. Like Bras- "Lift and Separate"
- (thin) running tights, providing both the support and less insulation ideas
- very thin wicking speedo-type briefs for support of the boys, PLUS very thin compression shorts over it (not too small, not too compressive) or boxer-brief type underwear -- not for heat retention but to provide a "sacrificial" rubbing layer of fabric -- similar to why people hike with two pairs of socks, one a thin liner sock. With this, definitely shorts or kilt to ventilate and keep cool