The term comes from pool, specifically from snooker, where the pockets are narrower than on a standard pool
table. When a "choke artist" shoots the ball, aiming for a particular pocket, the ball chokes out of the pocket and goes back onto the table because the
shot was improperly aimed. Choke artists repeatedly fail in situations when a crucial
shot has to be made and the pressure forces a bad
shot where the ball "chokes" in the pocket, wobbling back and forth until it is spit back onto the table.