How, specifically, does an electric meter measure wattage?

draythomp:
Sucking it faster than the meter can sense is not a good idea.

I've seen a video of that being done, and by the time you are putting in enough current to stop the meter from registering you need extremely heavy cables on either side and a supply good for tens of thousands of Amps - and the meter quickly collapses into a pile of molten slag. This is obviously highly dangerous as well as being contrary to the spirit of the assignment.