I have a player who runs a Mesmerist. One of his favorite tactics is to use Psychic Duel on the enemy. I have to ask him EVERY time what my NPC villain or whatever needs to do when this happens. But for some reason, I am completely unable to grok what on earth he's saying. He's not a rules lawyer (though he could be if he wanted) and knows the rules nearly word for word. But every time he tries to explain it to me my brain just glazes over and I let him tell me how to respond to his character's actions. I need to know the rules for myself, so could ANYone break them down for me and explain them in a concise, short form?