Oh, yeah, the old "baby wipe bath" offers. I got those back in 97 thru-hiking SoBo probably a dozen times. Usually starts with meeting an oncoming female hiker who stops to chat, then says something like "omg, wouldn't a shower and a candy bar be great right now?" Then she mentions something along the lines of "let's see what we got to trade" (one just said "Stone Soup?" which I didn't get until later.) Out comes a pack of baby wipes, she's got the "shower", wants you to bring the food/whatever else you got. Not gonna lie, I partook I think about four times (it can get sexually lonely on the AT long term.) One really was just a handjob wipedown, the others were more. Hadn't heard of it being part of the "culture" but it clearly was.
My daughter is about to turn 20 and wants to hike the AT, I've told her it's shit and try somewhere else. I hope that still isn't the culture there anyway. I regret now letting /out/ experiences be trashy street kind of behavior, just seemed like it was the norm at the time. Wouldn't want my daughter being exposed to it thinking that's acceptable - it really isn't.