What does "itching to say [something]" mean? In what circumstances could I use it?

Native speaker’s answer
Rebecca
To be "itching to" do or say something means to feel extremely impatient about doing/saying something, to extremely want to do something. Here, "itching to say it" means that someone desperately wanted to say something. Ex: I'm itching to go travelling now that pandemic restrictions have eased significantly. Ex: I was itching to say it, so I will. I can't hold it back anymore.