This is one of the fundamental tricks, and is performed by pushing the pen with your middle finger in a rotation around your thumb. It’s quite easy to grasp how it should be performed, but hard to master. Don’t give up after trying to learn it for 15 minutes, just keep trying!
Step 1: Hold the pen with T, 1 and 2, with 2 at the CoP, 1 closer to the rear of the pen and T somewhere between those two fingers.
Step 2: Give the pen a push with 2 while at the same time releasing it with 1. A circular motion around the thumb should now start.
Step 3: Let the pen spin all the way around the thumb…
Step 4: …and catch it.