Ass grabs for beer

Almost forgot this amazing series of events from friday night
me to dave mar: here is your beer
dave marr: no thats yours
me:no its for you
DM: no its not
(these same two lines repeat another ten times or so until)
DM: Ill take it if you grab that chicks ass
Me: sure, grabbing random chicks ass as she walks by
Random chick: (turning with a comlete look of shock and dismay to this bold manuveur)
Me: (to random chick) you may go now
and dave mar kindly accepts the beer and I return to the bar for another one. Looking back on this story it makes simply no sense at all, which is why it is so awesome