1. brass monkey a 40 of Olde English 800 mixed with some OJ. Typically one drinks the 40 down until the beer is level with the top of the cylinder of the bottle, then fill the bottle back up to the top with orange juice. It is a very tasty treat. 2. brass monkey Alcoholic beverage consisting of Rum, Vodka,and Orange Juice. This is the recipe of the drink that inspired the beastie boys to write Brass Monkey. It's a popular drink to have when your in high school. And I mean "IN" school. Teachers and faculty can't detect the smell of alcohol over the orange juice. ^^ this is news to me, i listened to that song a hundred times and never knew.. haha am i alone on this one?