The act of freezing a shit (preferably large) and using it as a dildo. Named after the thirteenth president, Millard Fillmore, member of the whig party. Butt specific. If used vaginally, it is referred to as a princess poopsicle.
"My shit has been in there overnight, it must be rock hard by now. Go grab it and give me a fillmore fudgepop."
by Dingus Jones May 1, 2007