When I get an earworm what gets stuck is the flipping chorus over and over again, or a few lines repeated until I want to bang my head against a desk with great force.

I'll share my nearly constant companiony, courtesy of Schoolhouse Rock:

Conjunction Junction What's your function?
Hooking up phrases, and clauses, and sentences like
He dropped the bags BUT the balloon wouldn't go any higher
Out of the frying pan AND into the fire
You can go up to the mountains OR down to the sea
something something something help meeeee (or something)

Repeat. Repeat again. Repeat again. Make children sing it too. Repeat. DO IT AGAIN!! NOW!!!