This is military fighter pilots' jargon. When the last missile is fired or when the ordinance has been dropped on target, it is then time to quickly get out of the area-of-operations. The pilot turns his plane towards base and shifts into after-burner. This has since been adopted by the civilian community to mean when a decision has been made, especially if it was a poor decision, you forget about it and press on with the next phase of the mission.

1. (noun) An abbreviation for stimulus check

2. (verb; stimmied) to get fucked by your government

getting to a destination and immediately turning around and going back home, commonly done by truckers.

In the restaurant world, this phrase describes the method by which a server will try to get a table out of his section as quickly as possible. This method is especially useful when dealing with customers who are not spending a lot of money and therefore, will not leave a big tip.
Popular methods include speedy food delivery, dropping the check before clearing plates, using short and speedy sentences, and anything else that will expedite the process of getting those cheap customers the hell out of there.

When you fart in a room and then leave without saying anything

To clarify the U.S. Navy term mentioned in another definition, it specifically referred to the ship's shafts/screws 'turning' and the boilers 'burning' and the phrase is in fact used (even though there aren't many steam-powered ships left) to indicate working hard, and steady momentum.

To start working and work hard. a U.S. Navy expression.

See turn to