cover (one's) ass

Translations
прикрыть (свою) задницу
He lied to cover his ass when things went wrong.
Он солгал, чтобы прикрыть свою задницу, когда дела пошли плохо.
Definitions
To take actions or make statements intended to protect oneself from blame, criticism, or negative consequences, especially in a situation where something might go wrong.
Words
ass

noun
осёл
cover

verb
покрывать