That's called deathgrip man, the unofficial name of being over saturated with porn or too much visual audio stimulation. You basically need to do a simple regiment of not jerking off. Try a week with no masturbation. Then in the second week, you can jerk it once. But try it with a condom on, and use different style with fingers or backs of hands, not gripping your member too tightly. In weeks 3 and 4, you can jerk it twice. Use lube and condom and try to get yourself to finish with a lighter touch. You basically have to train your brain to let your penis be more reactive to lighter touches than your hand.
I had this for a while, was able to go 11 days without jerking. I jumped back into pooning too soon, so I didn't fully recover. I was able to finish inside a provider once and only once, then had to lay off providers due to some work issues. When I got back into it, I was able to do 43 days without jerking, probably one of the toughest things ever. I then visited Ruby in Surrey and finished in her mouth quite fast. I still have trouble however, as the nofap fanatics on reddit say you need a full detox of 90 days to recover (which is almost impossible!). I can finish if the lady has solid oral skills, finished one time and only time after this with cowgirl. Basically it takes superior oral skills, or lots of dirty talk during sex to get me off.