This verse, although with choc-o-lat, rather than co-coa fat, is part of a 7 verse childrens game, late 19th/early 20th Century, and involved girls sitting in a circle and slapping one and two hands together and on the ground, with the tempo increasing as the game went on.
I will try to track down the other verses for you.
Yep. I just got a reply from the original Usenet poster, who very kindly cited the source pages: “It’s from the excellent online comic “Scary Go Round”. The song is first mentioned here and Shelley actually sings it here.”
As others have said, the mixed UK/US slang makes me very much doubt it has any trad source outside this strip.
Sounds like you’re on to something. 