What is the origin of the idiom "cover one's ass" and when to use it?

The phrase "cover one's ass" (often abbreviated as "CYA") is a colloquial expression that likely originated in American English in the mid-20th century. It is believed to have its roots in the idea of protecting one's rear or backside, both figuratively and literally. This expression is used to describe actions taken by individuals or organizations to protect themselves from potential blame, criticism, or adverse outcomes.