I think the joke works better if you sing the words. Also, I am a fan of a corny joke. The more cringe-worthy, the better, in my humble opinion. And who doesn’t need a good joke at this point in the week? I know I do.
I confess I know almost nothing about Good King Wenceslas. I doubt if I could sing all the words to the song. Heck, I can barely even pronounce his name. But now I know how he likes his pizza.