Don't feel stupid. I didn't realize it was so difficult to O during penetration in the beginning too. What can help is kegal exercises (
http://www.childbirth.org/articles/kegel.html ) and I bought this cheap little vibrating bullet online that works wonders (
http://www.nawtythings.com/bullets.html )! The best combination in the world is a vibration on top of regular pentration. I now get multiple orgasms from it! It takes time though, I've been having sex for 5 yrs and only just started getting multiples a few years ago. It's all about knowing your body. The only time I have ever had an orgasm without vibration during sex was when I was on top and the clit rubbed against him the right way and that one shocked me!! I apologize if this was TMI!
Oh and to answer your other question I think the wetter you are the better teh environment for the sperm to swim up there!