A note on the title, for my dead mother and grandma Selma and anyone else worried. I checked on your behalf and tripping balls has little to do with testicles. Those balls are an intensifier, the same one revving inside balls-out and balls to the wall. In origin story I, balls-out is the centrifugal governor on a steam engine, a spinning contraption with two metal balls that fling outward as the thing redlines. Full speed, balls flung horizontal.