I disagree about porn needing cocks, but I'd think that women should at least know how to get other women off. Despite this, a good portion of lesbian porn is just teeth sucking noises, dirty talk (which does nothing for me), and fake orgasms.
I get off on watching the girl totally lose it and start shaking like a leaf. That's the epitome of 3d porn for me. Most of it doesn't deliver, and I can't be bothered sifting through the petabytes of shit porn on the interbutt to find the few good flicks in existence.