A lateral in football is a backward pass between players on the same team. If a lateral is missed or dropped, it is a fumble. Laterals can be performed at any time, as long as the ball moves parallel or away from the goal line that the original ball carrier was running toward. There is no maximum on the number of laterals allowed per play.
There are some plays designed around using laterals, such as the hook and ladder and flea flicker. These plays are intentionally supposed to trick the defense, since laterals are so rare, that defenders will not expect a different player to have the ball once it has been caught or handed off.
A hook and ladder is where a wide receiver runs a type of curl route and receives a pass from the quarterback. As the defenders cave in, another receiver will have timed a run so that he is able to secure a lateral at full speed and run up the field without the defenders being in the right position to tackle him.
A flea flicker is seldom used in professional football, but can have massive results. The quarterback hands the ball off as if the play is a run, thus the defenders crash the box despite their initial assignment. The ball carrier then turns around and laterals the ball back before he crosses the line of scrimmage, allowing the quarterback to attempt a downfield pass to a receiver whose defender was hopefully fooled by the fake run.
While laterals might be known for causing turnovers if done incorrectly, studies show that they might be best utilized after a turnover has already occurred. When the defense recovers a fumble or picks off a pass, the offense is in no set formation to attempt to tackle the defender who runs the ball back. This is when laterals can be utilized to gain extra yardage, especially because offensive players are less disciplined tacklers.
In the 77 plays between 2002-2013 in which a lateral was attempted after securing a turnover, only three led to fumbles recovered by the offense while nine led to defensive touchdowns. The reward seems to be greater than the risk.
The most common time laterals are used is when the clock has run out and there is only one play left to be run. Players will continually lateral the ball attempting to slowly gain yardage and get past the defense. While not always effective, it has sparked some of the greatest plays in NFL history.
The "Music City Miracle" featured the Tennessee TItans and Buffalo Bills in a closely contested playoff game. The Titans would go on to throw a long lateral leading to a game-winning touchdown, but the play is considered controversial since it appeared to be a forward pass.