Christmas Is Coming is a traditional holiday song. It was sung by Randy in the Season Seventeen episode, "Black Friday".
Background
Randy arrives home after his first day as a South Park Mall security guard. He is pleased with himself for getting an inside job to be the first customer on the black Friday holiday shopping season.
Lyrics
Christmas is coming,
the goose is getting fat.
Please do put a penny in the old man's hat
If you haven't got a penny, a ha'penny will do
If you haven't got a ha'penny, then God bless you!