I'm writing an article about a myth in which two epic heroes facing each other before a single combat. The part I'm at now is when the two heroes start bragging about their abilities and things they've accomplished while at the same time they try to belittle their opponent by saying things like, "now tell me boy, you think you can handle a man?" or "before you were born I had been the champion of the champions." I think this part of the battle was mainly to diminish the opponent's self-confidence.
The modern version of this can be seen when let's say you want to have street car racing and start saying things like, "let's see how fast you can be on that wreck."
My questions are simply about describing this activity that people do before a competition, but since I provided two contexts, (one out of need, and the other out of curiosity), probably two words with a formal and informal register would be excellent. However, a neutral word is good enough. My sentences are:
The heroes started [verb]ing.
The racers were [verb]ing for a few minutes before going down the street at full throttle.