warning x-rated material

So, since being in college I have learned a lot. I've learned that most professors really hate the way I write, while the other few absolutely LOVE the way I write and have suggested for me to write a book. (Already have one and am trying to write another. never going to sell though). I've learned that you don't need to study and if you the little common sense you have you can pass a class with a B or A-. I've learned that prof's don't give a FLUX. (nice, huh?) I've also learned A LOT about female sexuality and sexuality in general. From gays to lesbians, to interracial couples, to straight couples, to fellatio and cunnilingus and coitus and other things thata re best not mentioned.
So, you're probabaly thinking, "umm..ok, where are you going with this?"
I'm trying to understand what is sex and why women have to orgasm. Most people say sex is penile penetration. With that being said does this mean lesbians don't have sex? Or could a dildo in the shape of a penis be considered penile penetration?
Also, do women have to orgasm? I mean just because you orgasm doesn't mean your satisfied. Just like how ejaculation and orgasm in a man isn't exclusive and inclusive. A woman can be just as satisfied with the whole occasion without ever having to orgasm.

So, what do you think? What do you think sex is? And do you think women have to orgasm?