a devastating sexual maneuver. start off by banging a chick doggy style while surrounded by a crowd of asians, preferably obese. then the crowd of asians all yell "banzai!!!" and start defacating. at this point the situation devolves into an epic struggle as to who can shove the most fecel mattter into each other's orafaces.
matt: wow look at tim smiling today
dave: yeah he just had a boston banzai
matt: that explains it
boy: wanna boston banzai?