I'm frequently able to cum while getting fucked. Just the way I'm wired. It doesn't happen every time and really depends upon the top. If we mess around for a bit before the "main event" and I'm really turned on, and if the top is larger than average, and if he has staying power, and if we're fucking face-to-face with me on my back (I've never cum while getting fucked in any other position). If those are the conditions, then there's a better than likely chance that I'll shoot while he's fucking me. Doesn't require stimulation of my penis either, I'll feel it build up and then cum will start spontaneously spurting from my cock. By far the most intense orgasms I've ever had.