If your dog is dragging her bottom on the carpet, it probably means her anal glands need to be expressed.
There are two small glands located on each side of your dog's rectal opening. Each gland holds a small amount of a noxious smelling substance. Most of the time, the glands express sufficiently on their own. However sometimes, the glands aren't completely expressed naturally.
I took my little Cocker girl to the vet and he charged me 75 bucks to explained to me why my dog was constantly scooting and licking her butter. Dogs have anal sacs that fill with a horrible smelling fluid that occasionally needs to be removed.