Do you know the feeling when you are about to fall asleep in class and you are trying very hard to stay awake, then it is like the whole room disappears and looks dark, and all of the sounds sound like they are very far away. This is a perfect example of a trance. When you get more practice, you will be able to control this feeling and be able to carry it with you for longer amounts of time. And to be able to do it without being tired.