I'm a 17 year old guy and I have started masturbating without any porn or dirty thoughts. I mostly masturbate in the shower and so I stopped using porn. I found the orgasm is much better. I enjoy it more and am able to focus on what I feel. The warm water, the cold shower bench, the warm tile under my feet, the jerking of my balls. I also have a shower mirror. And I like to put it on the ground and watch myself masturbate. It makes it a lot better and I recommend everyone try it.
I've tried in the shower, never seems to work for me. I think for one being on my feet just isn't the right position for me. It works when having sex, but not for masturbation. Far as not having any stimulation that to me is impossible. Your mind at least has to be thinking of woman, situations, etc... Now laying down in a bathtub on the other hand....
Now that you mention it, I haven't masturbated in total darkness for a year or two. That can be very intense.
I prefer to see what I'm doing when masturbating & to have something handy to ejaculate in or on to. But have several times done it in total darkness.