121 Cover for someone

(PW) protect someone

Please cover me, if I end up not knowing what to say at the meeting.

(free) cover (one's) ass

Vulgar Slang To take measures to avoid being held responsible if something goes wrong.

(dictionary)

Informal. to serve as a substitute for someone who is absent:

We cover for the receptionist during lunch hour.

to hide the wrongful or embarrassing action of another by providing an alibi or acting in the other's place:

They covered for him when he missed roll call.