Turning a guy on

My gf and I are playing with gender roles. I've never felt feminine, but she makes me want to be fucked hard and like a girl.

When it comes to turning you on when you're not in the mood, and i don't mean for a quickie, I mean let's have the most epic fucking sex of your life but your level of desire is really low in that very moment - how do I turn you on?

No simple answers necessary, I'm looking for your deepest, darkest fantasies.