Tell him you know what he is doing and that you are still in full charge of his life. You are the boss. During this time, your Saint may try your patience severely, especially if he or she has not been neutered. He has become more intense and excitable, and wants to thoroughly investigate everything around him. A female may act silly and not respond to known commands.
Some dogs go through chewing frenzies.
Some seem to be so full of energy and so full of themselves that they appear deaf to your commands. This can also be a very dangerous time for your Saintly puppy. He is totally exasperating. He behaves like an idiot and treats you with complete disdain. He is also a very large puppy.