That's an expression referring to the to ball tipped throttle control levers of an aircraft, pushed all the way forward to the full-throttle position. It has nothing to do with testicles.
It's not vulgar.
“The White House gets more like George III every day. Governor Christie never flew to vacations on a taxpayer supported Boeing 747, nor did his wife mooch off the taxpayers to the tune of hundreds of millions of dollars.”
Actually, neither did George III. His consort was very down to earth and well-loved in the English speaking world. Princess Charlotte is quite well known, and the Duke of Edinburgh only passed her last year for the longest serving consort of any King or Queen. Just over 57 years, almost the entire length of George III’s reign.