It is not normal for a dog to urinate in his own bed, even as a puppy. The cause is probably not marking, submissive urination, or lack of house training, but a deeper problem, potentially medical. Your dog may urinate in his own bed while he sleeps, releasing only a small amount or a full bladder of urine. Jun 16, - The causes for your dog peeing on the bed, can be broken down into medical and behavioral causes. We run through what you need to know.