Yeah, some idiots do it.. Most don't know why..
The idea was to use recoil as lateral (sideways) spread of multiple rounds, preferably a full clip..
Preferred target, .... a crowd, or group of people..
There is no accuracy involved, it is basically a "shotgun" effect, and often used from a moving vehicle. ( say, "drive by shooting"..
I actually don't know, and don't want to find out.
But, I had to try it myself. Not good. At least, not good with an M1911. Maybe a .32 would be better.
I've seen unsavoury folks at commercial indoor pistol ranges in Maryland, doing the sideways handgun thing ... They do it because they learnt eveything they know about guns from Rap videos.
I tried gan'sta style once, out of curiosity. at very close range (15 feet or so), I was able to hit what I was pointing at ... beyond that range sighted aiming becomes necessary, and gan'sta style is just a way of tossing lead downrange.