save someone's bacon
save (one's) bacon
To rescue one from failure, danger, or disaster; to prevent something bad from happening to one. Thanks for bringing me some extra cash—you really saved my bacon. The company is in dire need of new investors to save their bacon.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.
save someone's baconmainly BRITISH, INFORMAL
If you save someone's bacon, you get them out of a dangerous or difficult situation. Your mother once saved my bacon, did you know that? She lent me money when I needed it. Note: One explanation for this expression is that `bacon' is related to an old word for `back', so to save your bacon meant to save your back from a beating. Another is that in the past, bacon stored during the winter had to be guarded from hungry dogs. A third explanation is that the expression was in the past thieves' slang meaning `to escape'.
Collins COBUILD Idioms Dictionary, 3rd ed. © HarperCollins Publishers 2012