Spraying or Spray is a method of shooting that involves pulling the trigger until your magazine is empty. It is literally emptying your magazine without reloading or using shortburst, usually to hold off multiple zombies.
While this method is frequently used in zombie escape, it doesn't always help you on the positive side. When you are facting multiple zombies, it can still help to aim accuratly (preferably the head) and use short bursts while switching quickly from one target to another. Depending on the situation, spray can either save you or kill your entire team. Spraying when being close to zombies is a very good option, while spraying from behind towards your team will likely end up with a wipe.
A spray is a custom user-choosed image with a power of 2 resolution that can be sprayed on world geometry and brushes.