The act of finally following through in the comfort of your bathroom following a long period of constipation. The feeling of joy mixed with a likely feeling of discomfort due to the build up of matter since the onset of constipation creates the strained feeling of childbirth from the rear. Usually followed by a feeling of weary elation that is once again similar to that feeling following the birth of ones child.
'I finally gave bumbirth today.'
by MollyGenevieve May 12, 2005