Good topic....another one of those subjects guys often wonder about and don't always discuss or even KNOW how to discuss it!
I'm surprised some here have suggested (and apparently even USE) the aerosol deodorants (i.e. Right Guard, etc.) but if they do so with no negative side effects, okay. I can only imagine on scrotum skin though, tlhat there would likely be some "burning effect" felt!
DMW's suggestion with Gold Bond powder is good but he's correct in noting that using such (white) powder presents a real challenge around dark trousers!
(Same with talc powder)
I recommend the "proper" underwear always be considered...("proper" being for the season of the year and the comfort factor of course.) The looser the undershorts, the more room for "breathing room" (and discouraging perspiration) it would seem.
Having used baby oil (with Vitamin E. and aloe) in various jelq/PE sessions over the years, I still like to apply this oil just after showering "down there" and then pat off all the excess with a paper towel. Somehow, it seems to throughly condition the skin and might perhaps (?) has helped me to avoid the cited skin problems others have experienced here. 'Just a thought.