Couple of things come to mind; 1) I have never felt my partner cum in the sense of feeling him spurt. I have definitely known that he was cumming as he moves more deliberate, tenses up and will grab my legs, ankles or hips depending on position. 2)I have found that when it comes to pain, relaxation is probably the most important part.
My first time so many years ago, had some pain. But my first also took the time to seduce me, getting me so turned on that the pain diminished very quickly. The fact that we spent the weekend together with him taking his time made it very enjoyable to soon identify as a "bottom". He pretty much taught me all I know about gay sex, to the enjoyment of a number of men over the years, not least of which is me
Conversely, I think the relaxation part probably is why I have never been into the bar pick-up quickie. He's in a rush, just wants to get off, and I'm looking to be kissed first. Usually ended up involving copious amounts of alcohol (or weed in my younger days) and resulted in the walk of shame and a sore ass for days after. Not a whole lot of fun, for me anyway.
Relaxation, combined with a hot shower and some housekeeping back there. If you have a guy that likes to rim, wellllll