Well, some people want to look normal in the coffin you see, so they shoot themselves in the BACK of the head, it’s a little more difficult but you are much more presentable at your funeral. Let’s see now, if I cock the weapon first and hold it by the end of the barrel with my left hand I can pull the muzzle against the back of my head...now I just need to figure out how to work the trigger. Yeah, I think I can do it. I hope the first shot does it though, that second one would be a real ballbuster. Now, how do I get myself from here to that damned park after I’m dead? Oh, I know, it would be a lot easier to just lie down across the railroad tracks before I shoot myself. Then with my neck on the track I can just let the shotgun rest on the ground with the muzzle against my head behind the right ear and reach out with my right hand and pull the trigger. I’m sure I can manage that. I’m a born problem solver for sure! Oh wait, I’m gonna look like hell in the coffin after that locomotive and a hundred cars run over my head. Maybe I’m not as great a problem solver as I thought.
People who want to do that just stick the gun in their mouths, pointing towards the back of the head.