A very annoying, itchy feeling that one gets when they don't wipe their ass properly/completely. Sometimes you can wipe until there's no shit left but still suffer from this condition. Oftentimes this condition comes involuntarily and is not usually a result of lacking anal hygiene.
One way to counter-act this feeling is wiping with a wet cloth.
I had explosive diarrhea earlier today and it was impossible to wipe. I thought I got it all but the itchy sensation in my crack foretold of my incoming crusty ass.