Once you have your dog using the toilet area on a regular and systematic basis, it is very important to not confine your dog without access to the toilet area for long periods of time. If your dog is unable to hold it, he will have no option but to eliminate in the training area. And this occurrence will confuse your dog. He will no longer associate the toilet area with being the ONLY area in which he can eliminate. You will thus be making your job of house training your dog more difficult for yourself.
