GR translation: tickling just under his nose

[Mike Jing]

P43.18-25  Settling the window of his Balaclava helmet snug and
tickling just under his nose, resolved not to give way to panic, Mr.
Pointsman stands up, has to wait for blood to drain, resurge, bounce
up and down its million branches in the drizzly night, percolate to
balance—then limping, clanking, he heads back toward the car to get a
hand from young Mexico, who did remember, he hopes, to bring the
electric lantern. . . .

What exactly is "tickling just under his nose"?  Dose it mean that he
had a tickling sensation just under his nose, or he touched the spot
just under his nose to stop such a sensation?