If her clothes are off, you need to make as though lightening just struck within an inch of your foot; be awestruck, grateful to be alive, and incredulous of mother nature's handiwork. Say "wow" several times even if you've seen her naked three times that very day. If you have anything in your hand, drop it, and reach out and touch her. Don't always try to turn it into sex. Sometimes you just have to admire from a distance. And sometimes you have to carry her to the bedroom, lay her gently on the bed, and do work on that naked body. Both are integral to making her feel like heavens drop when her panties do.