Airflow, yes, but during the relighting of the bottom bits. The pipe tends to be slanted down on a light and relight, so a large flame will lick/eat/devour the chamber where the flame most heavily contacts the wall, as well as the effect of drawing through the air hole, will concentrate the flame at that point.
Another reason for lighting gently, drawing the tip close to but not touching the tobacco. And having the tobacco dry enough so it re-ignites without many BTUs being expended. Torch not thy tobacco!!
Another reason for lighting gently, drawing the tip close to but not touching the tobacco. And having the tobacco dry enough so it re-ignites without many BTUs being expended. Torch not thy tobacco!!