What is Going To The Mattresses?
1.
Going to war with a rival clan or family. Used in the mafia. Its when a mafia family sends someone out to get someone apartments and some mattresses for the soldiers of the family to sleep on while they hide out in saftey, waiting for a call to do something.
Sonnys thinkin' about going to the mattresses already.
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2.
to prepare for a protracted fight
From the movie "The Godfather":
CLEMENZA: That Sonny's runnin' wild. He's thinkin'a going to the mattresses already. We gotta find a spot over on the West Side
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