A combination of shit and celebration.
1: A self celebration one has on a toilet while defecating after an extremely large satisfying meal. Usually occurs after a large order of fast food. (ie chicken wings).
2: A shit that feels so good it demands instant celebration, or is a celebration in itself.
1: After the intense wing eating competition was over, I proceeded to the bathroom and held a shitebration.
2: He walked to the bathroom, boombox in hand, prepared for a shitebration after the long successful dinner.
3: His face showed shear delightment after returning from the bathroom, clearly he just had a shitebration.