I think potty training has created a higher awareness of the concept, but how does he know that poop is funny? It's not like I'm allowing him to screen new episodes of South Park...
Today, at the mall, he took Genevieve's bow out of her hair. I asked him if it was his, he said no. I asked him if it was mine, he said no. I asked him if it was Genevieve's, he said no. I asked "Well, who's is it?"; he responded in a gleeful shriek "Stinky poop's! Haaaaa ha ha ha!".
Why is poop so damn funny to all males? Is this another collective memory thing, like the enjoyment of Kung Fu movies and the ability to repeat baseball stats?
I have another possible explanation regarding the frequency with which this word is now uttered around my household. He just likes to hear himself say it, or he is enjoying the power the word now possesses since he is in the process of potty training. To be more direct; Payne enjoys saying the word and watching my head snap up in the manner of a buck that just heard a twig snap in the forest during peak hunting season.