I saw this video, and wonder about his words of "wisdom."
If turning the ignition on causes IAC to engage plunger fully forward, then there is no purpose in doing what he is suggesting.
Another person suggested, "The ECM “resets” the IAC valve when the car is operated at normal road speeds (35mph or more). During this time, the IAC valve is typically extended out all the way (IAC counts = 0), thus closing off the idle air passage. This helps the ECM “learn” the position of the IAC valve. Any time the IAC valve is replaced, this “learn” procedure should be performed."
And, I found a limited tech overview here, which suggested, "When installing a new GM IAC or Chrysler AIS motor, the pintle must not extend more than a certain distance from the motor housing. The specs vary, so check the manual. Chrysler says one inch (24.50 mm) is the limit, while some GM allow up to 28 mm on some units and 32 mm on others. If the pintle is over extended, it can be retracted by either pushing it in (GM) or by connecting it to its wiring harness and using actuator test #03 to move it in (Chrysler).