"To "ball" a "jack" refers possibly to the action of risking a shot in "Boules", or Bocce or its sister game Petanque. The jack in either case is the smaller ball for which the goal of the game is to either throw your team's ball closest to it, or to knock away your opponent's ball. To hit the target ball to another location, or to "ball the jack", is to alter the focus of the gameplay. To do so requires great accuracy, and assuming the game is scored for money instead of points (it is a drinking game, and takes skill and a bit of luck as well), takes risk as well, for in double or triple team play, you only get one shot (one ball per player). So to "ball the jack" is to risk a miss, and a wasted shot, at something that is really important to you."
