As stated before, luck of the draw. Also, if you're with someone who isn't privy to those sort of acts to begin with, communicate with them and see if they'd be wiling to try some.

My most recent ex was going to school for psychology to be a sex therapist. She was the epitome of "lady in the streets but freak in the sheets" and had the libido that would rival a bunny-rabbit. She watched porn and would frequently want to try things, so tried we did. I can say not all of it is comfortable or enjoyable. However, the things that I enjoyed that were a bit "pornographic" she also enjoyed. So, it worked out. Anyway, I was lucky, we had fun and I never felt once felt ashamed/self conscious/ or unsure when we were in the sack.