Stalling is to wrestling as is the block vs charge call in basketball or the offensive vs. defensive pass interference in football.

Couple things to keep in mind:
Is the bottom man able to do anything: base up, sit out, stand up, etc. or is he being overpowered by the top guy.
Is the top guy really working for a fall?

Those are the two questions I ask myself when I'm looking at them wrestle...

I also look for other things such as:
Does one wrestler keep looking at the clock vs. working?
What exactly is the wrestler trying to do with a move?
Do I know the move he'd throwing and why it's being applied?

I look at the action and I look at the spiral ride as doing, but not limited to, breaking the bottom guys down the throw other pinning combonations on him for the fall, twisting straight into a NF situation (since a 1/2 nelson is part of the move), trying to load them up for a possible stack??? I've seen some teams use the spiral as a ride/stalling and never move towards anything else, but when I pop them for stalling, I get the ol' "but he was off the hip..." excuse!

Riding the ankle does, in my opinion, two things:
Prevents the bottomman for getting away and could very easily become stalling,
Used in a 3/4 nelson stack.

Now you get into the whole discussion of an earlier thread of "coaching" if you use a general comment of "Action" or "Improve your position", etc. Any ref that being going to the KWOA clinic for the last few years has heard this approach of general comments said by the ref to stimulate wrestling/prevent stalling suggested by NCAA refs, evaluators, etc. in the spirit of preventative officiating.

Stalling is judgement. They key is consistency. If you're consistant in how you call it yourself, coaches and wrestlers will get used to it and know how to wrestle according to your interpretation of stalling.
In tournaments/duels when there's multiple refs,I usually ask the others how they call it or will call it so there some "levelness"/consitancy amoung the "crew" for the day/tournament.

I like the post, I wish more officials would post! I learn best through dialog and watching/listening from others.

"As soon as you think you know everything about something, you're dead and need to move on."