Toilet Paper is a consumable item.
It given by Zynga as a gift to all players who logged-on April 1, 2010
Some FarmVille users received 2 toilet paper rolls instead of the 1.
It allows you to toss toilet paper rolls to "decorate" a neighbor's barn as an April Fool's Day Event prank. Interestingly, the paper is not able to be used on Provencal Barns.
A FarmVille user's Pot of Gold has been "decorated" as well. [Pictures below]