[LunarBerry]

We had and have little doggies that does it and don't have parasites. A couple of reasons could simply be that their butt itches, kind of like we randomly feel a tickle/itch on a limp and scratch it. Good chance if there's hair tickling there. It could also be irritated if they have gone done #2 frequently. Or if you wipe after them, the wipes might be irritating them or something they ate may not agree with their rear ends ^^; Sometimes they may have a scratch there or if they produced a large amount off poo it may cause a little split on the anus and thus irritating it. Or even after a vet visit when they stick thing there it can cause some irritation later. Maybe they need their glands emptied as well, but I would think the vet would've caught that.