Well, it's been a while but I had to do this alot when Kai was a pup. He wasn't 100% trusted in the house until he was 9 months old. If I caught him in the act, I'd tell him "UH UH! Bad boy!" and take him out immediately. If he peed outside, I'd praise like crazy. If I didn't catch him doing it, I'd put him aside while I cleaned it up.