Find a nice solid tree to lean back against while your shitting, its not just shite you can push out while your dumping a chunk if your squatting with no support. As for wiping, if its messy and i've got no paper or spare clothing then scrape off the worst with twigs and polish off with nice wet grass or tough leaves. If your out with someone you don't like then use your finger and go give em a poo tash
We use the blue paper hand towels at work that we pinch from the office, its been on the march in london and even been on 15-1 a couple of times