As practice and I guess as a form of pseudo cognitive behavioral therapy I would call random places from the phone book and then deliberately stutter. I would introduce myself, ask random menu related questions and even direction to the store or establishment. This sometimes helps knowing that it's not the end of the world. It's sucks, it's embarrassing, when the person on the other end thinks you have a bad phone connection or you're cutting off. Even worse simply hangs up. All of these and worse have happened to me. Once again, it sucks, but it doesn't define you. There are variations of this one could practice. Even reading off something helps. Make some layups before you go for half court shots.