A phrase commonly used as an exclamation of an event that has just occured.

Likely to be heard in the Northern areas of England.

Famously used in the film 51st State by Shirley DeSouza aka Anna Keaveney.
Patty: Did you know that Marsha is a contract killer?

Welma: Well, shit in a bag and punch it!
by Pretty in wellies March 6, 2007
Get the Shit in a bag and punch it mug.