The pinky finger is the last and usually smallest finger on the far sides of the human hand, opposite the thumb, next to the ring finger.
A pinky promise is when two people wrap their pinky fingers around the other person's pinky and makes a promise. Traditionally, it's considered binding and the person who breaks the promise must cut off their pinky finger.
The chip is now spun in a 180 degree motion by bending the middle and ring fingers towards the palm, with the index and pinkyfingers functioning as secondary support.
The pinky then rolls the chip along the index finger and up, while simultaneously the thumb brings the outer chips back down so that the single chip may be inserted back between the two.
The index and middle fingers can then be used to move these chips into a new position between the ring and pinkyfingers.