Perspective of an exclusively hetero man to prostate massages - with a bit of openness to hear of the experience of others.
The inside of my ass has about an 70/30 breakdown of pleasurable vs painful and I have no real ability to know what sort of day it is going to be.
I have been blessed with partners that are not lacking in curiosity, and I am usually willing to go along with whatever new idea they have, or might have read or heard about somewhere. Over the years, that has brought prostate massage into play semi-regularly....and if it is hinted at during a handjob or blowjob, or during a normal massage, I will usually answer with some form of consent or encouragement to give it a try.
It is clear that going in fast and dry, with long fingernails or very rough fingers is likely to hurt - I also sometimes will have a sensation of burning or discomfort - even with slow prep, lube, spit or the like. I never really eat spicy, and I have no known digestive tract issues....just sometimes it is a very easy entrance that feels like barely anything intrusive at all - and other days it just is not on.
When I have had anal sex with female partners I am also acutely aware of "form on the day" and never have a very specific expectation that this act has to happen on this day - and will more likely err on the side of waiting for a better day.
Am I alone in this? Do others have theories that explain why it is one way on a certain day, and completely different on another...
But on a good day - and possibly one where I have not had a lot of ejaculation in the days prior - in combination with a real cock worshipping hand or blow job - a really good prostate massage elicits an orgasm and ejaculation so strong that I almost feel the need to check if any is stuck on the ceiling