> does jerking off for an extended period of time like 3 hours without ejaculation hurt the prostate?

And you do this for so long, why? What is your payoff? Just curious.
Why not spend this time working on enjoying multiple orgasms? It seems to me to be a much better and enjoyable way to spend your time. Using this approach and finishing with a climax will eliminate having Blue Balls, you will be able to bask in the afterglow of several orgasms after a short refractory period in between any two. The final pay off is that there should no longer be an ejaculation without orgasm--or, if not, at least this won't be something that will happen very often.

> And if i ejaculate afterwards is it ok/ if i don't cum?

In the normal context "ejaculate" and "cum" refer to the same thing.

Am I correct in believing that you mean having an ejaculation without an orgasm?

If so, the two are independent of one another. It is possible, although not common, for men to ejaculate without experiencing an orgasm. When this has happened to me it was after a prolonged (although no three hours) period of playing before going for a climax that was pretty anticlimactic. Just be careful of the phenomenon known a "Blue Balls". Experiencing this can be anywhere from slightly annoying to fairly painful.

There are many more muscles than those of the prostate involved in keeping you erect for a long time. If they get tired, they will simply relax and you will lose your erection. No damage. The extended overstimulation of your penis and all the nerve endings involved could cause you to lose a bit of sensation and reduce your response to the touch of other.

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