In this trick, it looks for all the world as if you were pulling a string right through your neck. Take a piece of string about four feet long. Tie the ends together so that the string forms a loop. Put the loop over your two thumbs. Put the double string in back of your neck. Slip the first two fingers of your left hand over the closest side of the loop which is around your right thumb. Let the string slip off your left thumb. Pull the loop in front of you, sliding the string off your fingers and onto your left thumb. You end up with the loop on your two thumbs in front of you.