Where can I get an accurate quotation of George Carlin's line roughly
"Do you know the feeling when somebody sinks an ax into your skull,
and the air rushes in . . ."? I want to quote it acccurately in a
scholarly article!

Here's one mention:

"It's like George Carlin says... "You know that cool blast of air in
the middle of your brain when an axe splits your head? I love that
feeling. But since that's the only way I can get it, I try not to get
too hung up on it."

From this website: http://john.clandominik.com/2003/20030519.html