This is a baseball term which refers to the act of two players on base both attempting to steal a base either simultaneously or with a short delay between them. This is an aggressive move by the offense and is rarely used. Some instances in which it might be used include late in a game, when the offensive team is desperately in need of one or two runs, or a momentum shift in its direction; when a catcher is known to have a slow reaction time to pick off a runner, a weak throwing arm, or perhaps an injured throwing arm; or when there are two fast runners on base known for stealing bases.
The delayed double steal is typically used when there are runners on first and third. The runner on first will attempt to steal second and draw a throw from the catcher. Once the catcher commits to throwing the ball to second base, the runner on third will attempt to steal home. If a double steal of any type is attempted, it is only recorded as successful if both players are successful. If one player is called out, the other player is not credited with a steal. This term could also apply to one player stealing two bases on the same play, though it is an extremely rare occurrence.