South Park is equal parts offensive and hilarious, and while my kids have never seen an episode (and I hope they don't for MANY years to come), they have known about "Mr. Hanky the Christmas Poo" for a few years now. If you aren't familiar with Mr. Hanky and aren't easily offended, here is a little linky-poo.
I found this little gem at Carlton Cards and the best part? It is part of their "Heirloom" Christmas collection (because I will be sure to pass this one down for generations to come, lol!).
When you press the flusher, it plays a little song. How precious!