Lil, I think that is fascinating... and that now makes sense to me where this is actually coming from, thinking on our positions when this has happened.
It really is hard to tell... because, again, the sensation prior to it does feel like you have to pee... but the sensation of it actually occuring is much different.
I also understand now why my favorite position is doggie style
The diagram is exactly where my bf has found his, er, uhm... success. Though I will say that when I was younger, this area was not very sensitive for me. Seems it has become much more so with age.