I agree with netav on this one. My own experience has been pretty much the opposite of your girlfriend's. Minus a small amount of "pre-cum" as we're all calling it :-), I've never been with a guy that got really "wet." But THEN I was with one that got really lubricated; at first I was really confused because it seemed like enough to be a full ejaculation well before that actually happened. Anyway, I guess everybody's different, and I don't believe it has anything to do with being/not being circumsized. Don't worry, you're normal! And you can always use other lubrications to make the whole experience better for you both!