cover your back
cover (one's) back
To act in order to avoid blame or responsibility for something or prevent oneself from experiencing negative consequences. I immediately covered my back by saying that I wasn't home when the puppy got out.
cover your backBRITISH, AMERICAN or
cover your assAMERICAN, RUDE
If you do something in order to cover your back, you do it in order to protect yourself, for example against criticism or against accusations of doing something wrong. He had covered his back by persuading Evans, chairman of their finance committee, to provide a written approval for the contract. Newspaper editors have to cover their backs against accusations of libel.