When I'm finger-counting base twelve I use the thumb as the counter. It's done on the outside of the hand and starts with the thumb on the tip of the index finger for one, to the first knuckle for two to the second knuckle for three, to the tip of the middle finger for four, etc. When I finger-count base sixteen I start with the thumb on the tip of the little for one, the distal knuckle, palm side, for two, the pendistal knuckle for three, the base of the finger for four, the tip of the ring finger for five, etc. I won't bore you with finger-counting base forty-eight; I never do it anyway, except to show that it can be done.