I only managed to reach the exact spot with a thin "tool", like a toothbrush handle, and not with my finger.
The easiest way for me is to lie on the side, when the knee of the upper leg is on the mattress, bring my hand from the back side and push this thin "tool" inside (not deep). this way I can easily control its exact position, stress and direction and stimulate the prostate.

Prostate is a mans g-spot. And that means: That spot is very sensitive. Touching it wothout preparation may feel uncomfortable or even cause more pain than lust. You should be aroused when trying a prostate stimulation. And You should relax, making everything fine for You. You should start slowly, using a finger to stimulate the anus region, sliding in carefully. Take a lot of oil or lube. When it feels fine, try to find the prostate with Your finger. It is not very deep inside; touch it carefully and find out what feels good. When it comes to prostate orgasm it may feel like You have to go to the mens room ... try it. It is a great experience!

I had one P-gasm in the shower one time. Fucking my ass with a double dong and jacking off with the other hand. Had what I thought was multiple orgasms for about 10 seconds. i was moaning out loud, "Oh God,Oh God' when it happened.only hit it once though I keep trying.

get a prostate stimulator Aneros while it takes practice once you master the technique you will have mind blowing orgasms

I tried with this toy for many time with no success
I even went for a long hours like 2-3 hrs for each session.

I have had mind blowing orgasms by stimulating my prostate both using a finger or dildo with lube. It’s an orgasm completely different from a regular orgasm. My dick is mostly flaccid during the process, but oozes a mixture of a substance that looks like a mixture of cum and precum (prostatic fluid?). I don’t touch my dick throughout the process and my whole body convulses and spasms when I orgasm as opposed to a regular orgasm which is concentrated solely on my dick. I also ooze a similar fluid from my ass when I orgasm but it’s mixed with lube so it’s hard to tell if it’s the same substance leaking from my cock. But the main difference is that after experiencing a prostate orgasm, I don’t loose my sex drive like I do immediately after a penis orgasm. This allows me to have additional prostate orgasms or one big penis orgasm.

I've always managed it with a dildo or a guy fucking me