The act of defecating on a pane of glass. For example, suppose you are at a party at a house with a room with a skylight. You would then climb to the roof, position yoruself above the skylight, drop trou, and proceed to defecate on the glass. The resulting image would be that of an eartworm emerging upon the glass. Known to occur most frequently in Philadelphia and its surroundings.
An earthworm has all the insult of a "pressed ham" with injury as well.