As always, the key is to have the right tool(s). In this case I am using a needle-nose pliers, but the important part is that your tool has somewhat of a taper. I also had good success with a “spade bit” (drill bit). It’s not in this video bit look it up and you will see what I mean. It has a nice shape to help grip as you are bending. Be careful not to bend unevenly, or the coil will become cooked. If this happens you can usually just press firmly back the other way and hold for 5 seconds or so to straighten it again. Using this technique I took a mm or two off of the diameter to make an extremely loose coil fit with just a little wiggle room to keep the banger from being crunched as it heats up– since quartz can expand faster than the coil resulting in cracking of the quartz banger!