Everyone is familiar with the story of Casey Jones who up at bat because of his massive
ego deliberately let
two strikes get by him before he (presumably) would made a home run, but he didn't. He struck out on the last one.
"Pulling a
Casey" in this case is used as an action of swindling. It simply means to deliberately flounder, mess up, or make deliberate mistakes in the beginning of a
game to encourage competitors and gamblers into thinking they have an easy win.
When in fact their opponent is quite skilled in the area of interest and is waiting for real money to arrive before they show off their incredible and stunning skill at the cost of everyone involved.
It's appropriate in settings of gambling like playing pool or even the shell
game.
In the shell
game the dealer pulls a
Casey with the new players by letting them win a couple of bucks by finding the pea easily enough under the shell.
But the dealer knows full well they're going to
bet more and try to win more - and that's when the swindle comes in. Once they have won their confidence on how "easy" the
game is.
Pulling a
Casey in a
game of
table pool for instance can show a pool-shark deliberately make bad moves like miss sinking balls and even scratching the cue to encourage bets.
And then after a few bad shots once there is real money involved - that's when the shark plays for keeps and takes the competitors and bets for all they are worth, hustling them for all their money.
"Did you see that ? I've
already won $5 from Justin in blackjack ! I'm upping my
bet !"
"Watch out, dude, he could just be pulling a
Casey on you."
