It feels like nothing but it is a state of hyperarousal masked by your body's natural opiates. This is the state we go into if we see an automobile accident is unavoidable.

It's best to come down from there. It is a psychologically dangerous place. Your body equates it with inescapable death. When you begin to come down you will be in high autonomic arousal. People can get reckless and hyperactive, even manic. That's why you need to know you are coming DOWN from that numb calm through hyperarousal, DOWN to parasympathetic calm.

If you are doing talk therapy and going numb you really need to stop doing trauma work and do ego building and other stuff. Don't retraumatise.