I know that when someone misaims and hits my cervix, it hurts...
It's actually hard NOT to stimulate mine. I have a tilted uterus and it sits really low and at kind of a weird angle. It made sex ridiculously uncomfortable for a while until I figured out WHY it was so uncomfortable.
Anyway, I can easily rub pretty much the entire thing myself, and my opinion is that I either really don't feel much sensation or go "OW!"... without much in between. That may not be true for all women, though. I've certainly heard of women who enjoy it.