As the “Side Grip”
The side grip is a technique for shooting a handgun in which the weapon is rotated about ninety degrees and held horizontally instead of vertically (as is normally done). Shooting a gun in this way has no practical benefit under most circumstances and makes proper aiming very difficult, but the style has become somewhat popular in rap culture and among street criminals (who do not often use the gun sight) due to its portrayal in U.S. film and television since the 1990s.
More hilarity on the Wiki Page – HERE
Sadly there is no mention of Birdman Weapon Systems – Homeboy Nyte Sytes