I wipe?
But honestly, I get sweaty down there, and seriously, if it feels like it's too slippery and might threaten to smell nasty, I go to the bathroom and wipe with toilet paper. I'm not sure how bad swamp ass happens, since I'm not prone to it except during a hot humid spell. However, toilet paper is often available wherever there is a bathroom. It's a great interim fix. Have also washed my underarms in a bathroom and followed with drying off with the provided scratchy brown paper towel to get rid of unexpected midday underarm odor. Works like a charm until you can get a bar of soap handy. And don't forget, you can always wet a paper towel and add a dab of liquid soap that's provided in a public bathroom, slip into a stall and swipe clean that nasty problem.