Depending on where you live really ....if youre an American and living in Alaska ,it might send others standing near you a message that you have cold thumbs....:)
You feel insecure or are holding back something you want to say or know the other person wants to hear. It may be a childlike form of comfort or thumb sucking trauma from your past. You many not like the way your thumbs look OR because they way your hands are formed it is simply a comfortable position. That will be $50.00 please. hahahahahaha