I checked out the origin of the expression of Balls Out, and surprisingly, rather than a vulgarity, it comes out of the English Steam Engine Technology.
There, rotate two iron balls, and to make this simple, and as they were at full speed, they were said to be "Going Balls Out." As I worked on the piece,
I began to see a leaping, hurling figure ~ from the ballet ~ and the word Jette came to mind. RG