Carson gave Addison a piece of their mind.  Addison talked badly about Carson behind their back.
Carson found out I had been bad-mouthing him behind his back. Uh oh.  What happened, did he confront you? Yes, he did.  He really gave me a piece of my mind. Well, if you were talking about him behind his back, do you think you deserved it? Yeah, I guess I did.  I should have said what I said to his face. Hopefully this won't have a lasting impact on your relationship with him.