Potty (or poop) humor

So, lately Z's favorite new word is 'poop.' He loves to use the word in every possible instance. One game he likes to play (well, not really a game to his unsuspecting 'victims') is to ask if you smell something. When you innocently ask what, he yells "It smells like poop!" He laughs and clearly basks in the knowledge that he's pulled one over on you.
But his favorite new game is this: he asks us what his name is and we tell him he knows his name. He gleefully exclaims, "Zavion!" Then he asks what his full name is (we taught him to say his full name a while back) and again we tell him he knows it. Then he gets a devilish smile on his face and responds, "POOP name!" He laughs hysterically, as if watching Jerry Seinfeld perform at The Comedy Club. And, it doesn't help that Colin is right there laughing with him. He says he just can't help it, that it's such a funny word. :p And, at that point, I often think we could use a little less testosterone and a little more estrogen in our house. *Sigh*