Can be either positive or negative: good shitter or bad shitter. When said positive or negative occurs, exclamation is "shitter shitter(!)", with or without exclamation mark, as appripriate.
"My cat has died". Response: "Shitter shitter." Alternatively: "I have come into an unexpected source of funds". Response: "Shitter shitter!"
by Spruce von Moose August 16, 2006