I've had that "stings when I pee" thing happen after really long rides, but it's gone in less than 24 hours...I think the urine burns even slightly irritated/chafed skin. I've gotten it after 10 hour runs, too- and it really helps prevent it by keeping all urine off the area during the ride (like if you have to stop to pee in the bushes, dry off carefully) and using lots of Udder Balm down there.

Nanci