Why is my dog scooting on the carpet? What should I do?

Three possible causes? First, it is possible the dog has worms. If it is a long haired dog, it may have fecal matter matted around it's that has dried and is pulling and itching. Or, most likely, the dog needs it's glands expressed. These glands are on the sides of the and normally regular bowel movement empty them. But sometimes they get blocked a bit and they feel full and the dog "scoots", trying to squeeze the glands to empty them. They can leave brown watery stains, and the fluid has a foul, distinctive "dead fish" smell,as we call it. Take the dog to the vet and have the vet tech express the glands for you; most places charge $5-$10....best thing, if you can take it, is to ask the vet tech to SHOW you how to do it, so you won't have to pay for the service again, but just do it yourself.