i don't give a brass razoo - A very rude way of saying you don’t care and are going to be

A very rude way of saying you don’t care and are going to be extra rude about it.

Your mom called again. I don’t give a brass razoo, I’m gonna text her a raccoon and a middle finger.

Your cat pooped on my shoes again. I don’t give a brass razoo, I’m gonna throw it in the trash and laugh.

You forgot my birthday again. I don’t give a brass razoo, I’m gonna steal your pizza and eat it in front of you.