@Fire Dan, I understand your concern and being grossed out. Dogs often rub their butts on carpets to relieve an itch. Dog butts get itchy, and they can't exactly reach them, so sometimes scooting is the only way to relieve it. But there are a few other things that can cause it. One thing in particular is anal gland issues. Or anal sac disease. We cover this in more detail here. Other medical issues include parasites or even growths from serious diseases like cancer. So while your friend's dog may just have an itchy butt, it could mean something else. I agree with my colleagues and suggest you take your pup to the vet.the dog keeps scooting her butt on my carpet