A ball and socket occurs when one bro goes in for the fist and the reciprocating bro acts as if he is gona bump too, but instead grabs the bros fist and shakes in a pivoting motion making for an awkward moment. Thus the ball and socket has been created.
Bro 1: Fuck yea! (Goes for the fist bump)
Bro 2: (secretly going in for the bro move with alterior motives, and grabs the fist and shakes)
Bro 1: awe shit man the ol' Ball and Socket!