I always psyche myself into believing I'm some hot little sex kitten. I play out in my mind what I'd like to do with him and get very graphic. This always keeps me going. When entertaining a man one cannot neglect the setting. Make sure it's a place where both of you can be relaxed.
Comfort is a major key when becoming intimate.
I mean really know them. Most important for me is to trust your partner and to be loving with each other. I feel so vulnerable in intimate conditions, that I would rather wait for the loving relationship, rather than settle for some cheap sex. Don't get so set on the goal of orgasm. Enjoy sex for the moment and give attentions to the whole experience.