Picks:
A pick occurs whenever an offensive player moves in a manner that causes a defensive player guarding (3.E) an offensive player to be obstructed by another player. Obstruction may result from contact with, or the need to avoid, the obstructing player.
A pick can be called only by the obstructed player and must be announced by loudly calling "pick" immediately after it occurs.
Call the pick immediately. If you wait too long, you lose your window of opportunity to make the call.
In addition, the obstructed player is then allowed to move to recover the relative position lost because of the pick.
Then the picked defender catches up the relative position lost because of the pick. If they were trailing by 9 feet, then they get to catch back up to 9 feet away, but does not get to set up right next to the offensive player.