Puppies use their mouths the way children use their hands - to pick things up, feel textures and generally understand their world. While swallowing a mouthful of grass or dirt every once in a while won’t hurt your puppy, foreign objects like rocks, sharp twigs or rotten food could do some damage. As your furry friend matures, you’ll need to keep a close eye on your puppy whenever he’s outside and reprimand him when he picks up something inappropriate. Puppy school – You may want to consider puppy school, where your puppy can learn to follow basic commands. Your veterinarian can help you find a good school. “Drop it!” – One of the most important commands your puppy will learn will be "drop it," which will teach him to immediately spit out whatever is in his mouth.