The act of defecating in the baby changing station at a public bathroom, then folding up the door leaving a nasty surprise for the next parent. This act comes from the idea of an "upper decker" or a "top shelf".
The toilets in that rest stop are disgusting. I couldn't take a chance to rest my cheeks on one of those seats. So I left the men's room a diaper decker.
by Magoo Wes March 26, 2010