Cover your ass

"Cover your ass" means that you need to make sure you have done everything you can to protect yourself in case something goes wrong or someone blames you for something bad.

Imagine you are playing with your toys and your friend comes to play too. You know that your mom told you to clean up your toys before your friend comes over, but you forgot. If your friend trips over your toys and gets hurt, your mom might be upset with you because you didn't clean up.

So, to "cover your ass", you could quickly clean up your toys before your mom finds out, or you could tell your friend to be careful and explain to your mom that you forgot to clean up. This way, you are doing everything you can to protect yourself from getting in trouble.

This phrase is often used in grown-up situations like work or legal matters where people need to make sure they have all the right paperwork or evidence to protect themselves from being blamed for mistakes or problems.