I've found "ass flossing" to work much better than regular wiping.
It is especially good at the house of a friend or even a neighbor.
You take a towel - ideally something long, but the lacey show towels work well too. Grab ahold of one corner in your right hand, then whip the towel between your bare legs and gasp ahold of the opposite end corner with your left hand.
Then squat down a bit, push out hard on your ass, and then raise your hands up as high as you can.
Then wave them back and forth, one high, one low until you feel a vague burning senstion just behind your nuts.
Afterwards, just leave the towel on the floor so that whoever comes by next knows how clean you got.