Gas welding; popping

OxyAce welding. I know the popping sound I occassionally hear is
because the tip is too hot and either a spark or something else is
igniting the gas while it's still in the welding tip.

GOOGLING around to validate this understanding and ideas for
correcting the problem, I find the following statement: " I keep a
piece of hard wood handy and play the torch on it to get a little burn
going. I then rub the end of the torch in the burning wood and POP,
the torch tip is clean and flowing."

I don't understand what he's doing. Is he saying that while the wood
is on fire he rubs the orifice of a lit tip against the flaming wood?
Won't that put the torch out? won't that produce unexpected
back-pressure on the torch? how is this cleaning the torch tip? - Mike