ok i'll teach you.
First, you need to put the tip of the pen between your index and middle finger. the other tip collides with the fleshy part between thumb and index.
Second, move middle finger away from you , and the index finger towards you. this will create a pressure on the fleshy part. try to get the optimal power(you should repeat this many times)
Third, release the pen from the fleshy part. it will creates a spiral movement. repeat so it won't fall of your finger.
Fourth, now , when the tip was traveling spirally , move your index finger away from you. it will move the pen back to the starting point.