How to adjust spark plug gap

I was wondering if anyone could explain the actual mechanism for adjusting a spark plug gap—specifically, what tool is used for the adjustment itself? I think I have a decent handle on how to measure the gap using those feeler gauges and whatnot, but I am somewhat unsure about the physical process of making the tweak.

You can just use a screwdriver to peel back the electrode a bit—or if it’s being particularly stubborn, just grab a hammer and bend it into shape... 🙂