Finger Control

Tell your subject to put their hands together and interlock their middle, ring and pinky fingers together and their index fingers in a V shape with their bottom finger segments touching. Their hands should now look like a gun with a split barrel.

Now put your index finger between theirs and knock your finger around within theirs and tell them to close their fingers together, then tell them to open their fingers again and repeat.

Do this five times and after that tell them to open their fingers again then put your hands in fists and put your fists on the left and right sides and their hands in the middle, then rotate your hands around theirs as if you were turning something like a pepper grinder. If you followed these instructions correctly their index fingers should slowly close in without them controlling it at all. If their fingers didn't close then try again.