28 [M4F] What is your "impossible" fantasy? What gets you off that you know would never happen in real life?

I think we all have a fantasy or two that we know probably will go unfulfilled. Sometimes, life's circumstances just make it impossible for us to live out these fantasies and yet we continue to think about them while we bring ourselves to a strong climax. What is your "impossible" fantasy? What gets you going about the fantasy and how long have you had this fantasy for? Bonus points for people with highly creative fantasies....