This saying dates back to WW11 when the American army suffered a lot of injures caused by their our troops, at the time the USA army had a large influx of cowboys in their ranks. These cowboys was unused to modern weapons esp. the new GA12Z bazooka. This particular weapon had a deadly backwash which was capable of inflicting great damage on its handlers and loaders, so they had to develop a warning shout when about to fire the weapon, hence the saying �tuck your hooters into your bazookas�