I've read that when a dog drags its bum on the ground, it most likely has worms. My 14 week Lagotto does this occasionally and it's usually if he's just done a poo. Today he did it in the kitchen and hadn't done a poo. Could it be something apart from worms? The reason I say apart from worms is that he's been wormed regularly, is healthy and has recently had the thumbs up from the vet.