Anyway in my opinion blowing on the coil while energizing isnt gonna harm much as long as you dont over do it because you are still applying power and as one person already said really just making your battery try harder. However i believe that when you blow it while still hot but after letting go of the battery you "super cool" the coil causing it to contract quickly. This , IMO, helps in the cleaning process but also may shorten the life span because you are expanding and contracting the metal faster.
Maybe one of the "Old Schoolers" can chime in and let me know if im thinking correctly.
I am not really old school, but I have a method that a) makes scientific sense to me, and b) works consistently.
This is exactly what I think is happening... a gentle puff of air
while energizing the coil will speed the burning off of residue by increasing available oxygen, overdoing it may cause a very hot coil. Overheating the coil will shorten its life, or may melt the plastic air holes closed, and create a draw problem.
Blowing
after releasing the power button is bad. It causes the coil to cool rapidly, causing rapid contraction, which will weaken or eventually break the coil.
Personally, for my LR atties, I use a method described in another thread here, that aims at keeping a consistent, but not too hot dry-burn temp.
1. Hot water rinse, air dry if there is time.
2. Use a bigger battery, (mod?) Dry burning with a standard bat is probably going to over stress the battery.
3. Cycle the power button for a few long presses, 3-4 secs on, < 1 sec off, until you see either the very first sign of glow, or lots of smoke.
4. Short power bursts for 15 - 20 seconds to maintain that temp. On-off-on-off a few times a second, with enough air puffs to clear the smoke.
5. Stop blowing, and allow it to air-cool for at least a minute before using.
My atties either break in the first few days, disappear to the vape-faeries, or break when I drop my ecig, clumsy me. I have only popped one attomizer during a dry burn, and it was before I started using this consistent temp methodology.