THIS IS ONE OF THE MOST IMPORTANT lessons your pug needs to learn. Unfortunately, for this breed, it's also one of the most difficult. Pugs can be cavalier about where they eliminate — indoors, outdoors, what's the difference? The keys to successfully housetraining a pug are using a crate, establishing a routine, recognizing elimination behavior, understanding dog physiology, offering consistent positive reinforcement, having plenty of patience and, above all, maintaining a good sense of humor.