When you place your hands into your pockets and have a little fiddle with you Willy.
Ryan: "Hey check out this pic of a hot chick"
*BANG* - a noise can be heard from a seperate cubicle in the work place.
Ryan: "What was that noise?"
Byron: "It was Nick playing pocket ball"
Ryan: "Look at that dude with his hands in his pockets! jiggling around"
Nathan: "Yeah he is playing pocket ball"