Bicycle riders regularly use "butt butter".
If the nips start getting chafed, I use my chap stick.
I once got a bad case of chafing on my inner thigh, and had nothing to help it. ...I use synthetic athletic boxers now, and that helps. But on that trip, I begged an ace bandage off two ladies, and it was a trip-saver.
TMI warning... I used to have a lot of trouble with burning/itching in the back door area, to the point I was using a lotramin anti-fungal cream that helped most of the time. But regular use of that actually made the problem worse. So a visit to the doctor, and he explained what might be happening, and it turns out he was 'zactly right: When I hike, the steady bouncing can cause a tiny amount of stuff to exit, and that stuff can be really irritating. I found that stopping and doing a TP cleanup made all the itching and burning go away. (You were warned about the TMI).