What is balls to the wall?

"Balls to the wall" is a slang phrase most commonly used in the United States and the United Kingdom. It is typically used to describe a high-risk, all-out effort or action. The phrase is also often extended as "go balls to the wall," suggesting a willingness to take on a challenge without reservation.

The origin of the phrase is thought to be rooted in aviation, where the handles controlling the throttle of an airplane's engine were often shaped like balls, and pushing them "to the wall," or the end of their track, was a signal to pilot that the engine was being run at its maximum power.

Today, the phrase has come to be associated with sports, military operations, and other intense activities where a single moment of unyielding action can make all the difference. The term is often used in a figurative sense to describe someone who is working or playing at an intense level, or to describe a situation that is fraught with risk or danger.