I started to spin a basketball on my finger when I was about 10 years old. I would always watch the Harlem Globe Trotters on T.V. spinning it all the time and playing around with the crowd. Seeing this urged me to learn how to accomplish this magnificent feat.
This is how you do it:
Step 1: Find the right basketball
The first step is to find a 28.5 or 29.5 sized good gripped leather basketball. This will allow you to grip the ball better and it will be easier to control than a different type of basketball.
Step 2: Positioning body
The second step is to find your strong hand, and spread your fingers out as far as they will go and flip your hand flipping over with the palm facing up. While your hand and fingers are ready, make sure you are standing up straight and your feet are shoulders width apart.
Step 3: Positioning hand and laces
The third step is to hold the basketball on all your five finger tips with the basketballs logo facing outward. If the ball is facing outward then all the laces should meet at the bottom of the ball where your fingers are located.
Step 4: Spinning the ball and corking it back
My technique is different from most people. As the Laces are on your fingertips, cork your strong hand wrist (my right hand) inward to get a corking motion. Once corked you are ready for the next step
Step 5: The actual spinning of the ball
As you begin to uncork your wrist, throw the ball about five inches into the air as it gets released from your hand. This will make the ball get a quick, perfect spinning motion. While the ball is on its way down, straighten out your index finger (any finger) really and catch the spinning ball.
Step 6: Keeping the ball spinning
As you catch the spinning ball, make sure to keep your finger nice and straight. You can either spin the ball on your fingertip or your fingernail, whichever feels more comfortable. The ball should just keep spinning by itself for about 6-15 seconds based on balance and cork spin speed. If you want to keep the ball spinning for longer, use your off hand (the one not spinning the ball) and sort of slap at the side of the ball. This should spin the ball faster and keep it going. Make sure not to slap too hard or the ball will fall off of your finger.
Step 7: Different things/body parts to spin the ball on
Once you get good at spinning a basketball on your finger (this can take years) then you can move onto more tricky maneuvers. You can spin the ball on fingertips, fingernails, knuckles and even a pen or a pencil. In order to accomplish this feat, the spinner needs to be very gentile and still. Along with spinning on different items you can also spin different balls such as soccer balls, footballs and medicine balls.
Now that you now know how to spin a basketball on your finger, go out and try it. Once you start it is hard to stop. It is such a fun and pleasurable thing to show off to your friends.
Best of Luck