Identical to a donkey punch, except performed with a roll of quarters or other coins held in the fist (simulating a set of brass knuckles). This provides a much harder impact that is more likely to knock your partner unconscious.
I lost my job at the bank after getting caught using company property to give the branch manager's wife a brass donkey.
by Johnny Panic November 20, 2007
The brass donkey punch is very similar to the original donkey punch. For you will be doing your girl doggy style and as you are about to climax you will punch her in the back of the head in order to make your vaginal wall muscles tighten to better your orgasm, but with the brass donkey punch you have brass knuckles on which even betters the punching effect and tightens the vaginal walls more.
by Tsquare May 1, 2005
Similar to the Donkey Punch, this sexual maneuver incorporates brass knuckles for that extra kick to get you over the hump.
After the original Donkey Punch lost its luster, Matt broke out his brass knuckles and Brass Donkey Punched his fuck buddy Sarah.
by Mario N. Luigi February 27, 2009