Do you honestly think that it's unrealistic for 99% of women? I mean, me and my girlfriend have been together for a little while, and she happens to be one of those awesome deep-throat whilst swallowing kind of girls. And, when she does that, I feel like my testicles are about to explode it feels so damn good. And, yeah, it does feel 100 times better when you AREN'T being "jerked off".
If you are unsure, I suggest jerking him off with your mouth close to his dick so that you get a little in your mouth, but not all of it. If you like it, you can try the other way.