I've read posts here saying that:

What does "The valve cycles each time the ignition is turned off" mean exactly?

Just curious, as I've been trying to pinpoint a faint, metallic rattle sound my car makes when in gear, and the curious thing is it seems to temporarily go away (or at least become barely noticeable) after I redline it, or turn the engine off/on (such as when getting gas).

I'm wondering if it's "chattering" until it gets opened/closed... if that's what "cycling" means?

 

That quote is actually a very detailed description of what that valve does.
And "cycling" is just that... when the key is turned to 'OFF', the APV motor cycles the valves fully open and then closed.
If you open your hood and have someone in the car turning the key from 'ON' to 'OFF', you can actually hear the valves cycle.
I usually hook-up a 12VDC supply to the motor to continuously cycle the valves.

 

turn it on and rotate the valve cylinder to the open position, then turn it off and rotate it back to the closed position = a cycle