A not so subtle variation on the more common STUNT man shot, popularized by rugby players, where you snort a line of salt, take a shot of tequila and then get punched in the face.
Where as with the STUNNED man, you snort a line of coke, shoot the tequila then punch the bartender in the face.
This was made popular by a group of hard charging 30 year olds in their prime.
Big Ron had to leave the bar quickly after doing a STUNNED man shot at the bar.