After draw? Is that like after glow?
So you mean a bit of a puff after the puff, with no power?
After power is applied the metal coil will still retain heat capable of vaporizing the juice.. The heavier the gauge the more heat will be retained, and the more important it is to use all that heat you built up in the coil. The retained heat cooks the juice and increases your gunking.
The idea is stop firing a second or two, before your draw is complete, depending on gauge of wire, and use the remaining heat for complete vaporization. Once the coil is below a certain temp it won't cook the juice.
At low wattage, higher gauge, you won't need more than a second, or split second, So just release right before your draw is finished so you draw that air in to cool the coil.
Temp control mods basically do just this for you during the vape.. You could be vaping at a temp without having much power applied. They use the principal of retained heat in one way. Also you will get slightly better battery life taking one second off per vape like tc. But you still have to let off a little early to use that remaing heat.
If you've ever test fired a coil.. Then a few seconds later touched it you see how much heat is still in that wire after power is removed.. 200 vape a day 2 seconds of cooking after each draw and you have equivalent of a pan on the stove carmelizing gunk.
Most have the habit of stopping their draw before letting off the fire button.. This is why they have so much trouble and have to rewick so much.... Just switch it around.. Let off first.
Also as mentioned it removes Vapor from chamber so it doesn't condensate back down onto the wicks.
