Determine whether or not your lacrosse head has too much whip. If you've been practicing with the stick and have been able to hit targets consistently, your stick is probably fine. However, if you've noticed a sudden lack of consistency when passing or shooting and the ball just always seems to fly lower than you want it, your stick may have developed a whip.
Adjust the shooting strings to correct whip. A typical lacrosse head has between two and five shooting strings that are usually made of shoelace. The top shooting strings should be the tightest and the lowest should be the loosest. Adjust your strings accordingly. Untie each string and retie them again so that they go from loosest to tightest starting from the bottom up.
Test your pocket by running a lacrosse ball up and down the inside of the pocket. The ball should travel smoothly from the bottom to the top. If the ball seems to get caught on one of the shooting strings, untie and loosen that string and adjust accordingly.
Try throwing a ball or two to test the stick. Using a regulation-sized lacrosse ball, shoot at an imaginary target on the wall, following through naturally and pointing your stick at the target. The ball should hit as close to the target as possible. If the ball whips towards the ground, continue to adjust the shooting strings until you reach your desired amount of whip.