The more wide-ranging thread on this song is this one (click). I'd like to add this song to my repertoire, but I haven't been able to get the nonsense line straight. You can't sing a song like this one unless you can sing it well. It loses all its entertainment value if you can't zip through that tongue-twister.
This thread has a discussion of the nonsense verses in songs, but I still don't completely understand the difference between "burden" and "refrain" and "chorus." I think this nonsense line is a "burden," but maybe not.
-Joe Offer-
(e-mail sent to requestor with a list of our various versions of the refrain - I got a nice note of thanks back)