I add an emotional connection between the two characters. It's too easy to make a scene trashy when it's erotic romance, so you have to delve into your characters' psyche and show WHY they are there. It's not just for the physical gratification, it's something more they seek--a union of the soul.
I need a sex scene with romance, otherwise it's just pr0n. I like to see some romance as well as a forceful but tender hero. Good luck, Becca!