I have a 4 month old puppy and if he is in the house and has to go to the potty he will pee on a puppy pad. When we take him outside to use the restroom he pees without a problem. Pooping is the hard part; over the past month he will not poop outside. If we catch him about to poop inside we will take him out and he will just play. And when we take him back in he will poop as soon as we leave the room or walk around the corner. We got him to pee outside by giving him a treat as soon as he pees outside. Is there any training tips we could try?