I think I figured out that I'd go numb most often when I needed "rest." It was kind of a primitive way for me to regulate myself, how hard I was working in therapy or on my own. I don't get numb very often anymore, feel more "balanced" and get better clues from myself when I need to relax or take a break or when things are getting too intense for me to deal with well so I back off before I wear myself out.