My 13-month old thinks being told no is a funny game. He laughs every time we say it. I have no idea how this started, as it seemed like he was starting to understand what no meant (always accompanied by removing him from the object). Now it's a game. The louder/more harshly it's said, the funnier it is. I tried the clap-growl from the happiest toddler on the block book and that was downright hilarious! Ah! Any advice?