originally referred to as giant blind worms that "live in the ground," this refers to the act of drinking a large quantity of beers, generally Budweiser, but not limited to this.
Also see Select Tremors (Budweiser Select)
and Down-Home Tremors (American Ale)
and 40oz Tremor (40oz Budweiser.)
"Hey man, what are you doing tonight?"
"You know, Killin' Tremors, you should come over and do your part."