I was going to mention the idea of trying to 'relax' in some way that 'elrique' posted above.
Another suggestion my be to explore the
Art of Cunnilingus. There is an excellent book by Violet Blue titled,
“The Ultimate Guide to Cunnilingus”, 2nd edition and published 2010, How to go down on a woman and give her exquisite pleasure. There are some excellent suggestions in relaxing, patience, and the arousal nature of this sexual activity.
Cunnilingus is an age-old practice dating back as early as 300 BC which is the practice of oral stimulation of the females genitals. When people who enjoy oral sex, enjoy it purely for the sensation and that both partners are active. The woman who receives cunnilingus is just as much a participant and entirely up to her in the act as the person who is doing the licking. There is nothing that compares to the warm, wet feeling of a lover’s mouth caressing your most sensitive (clitoris) and private parts. The intimacy and sexual closeness that cunnilingus provides is incredibly arousing for many people. When you're with your lover, going down on her can provide a rush of erotic intimacy that is a very powerful aphrodisiac. Some people also view it as an appetizer to the main course. Having a skilled and knowledgable lover, who knows female anatomy and how women like to be licked, is a circumstance that many women dream about. The softness of a pair of lips, the heat of a mouth, and the slick feeling of a tongue sliding around and over the vulva is a sensation like no other. The feel of a lover’s mouth on a woman’s genitals offers sensations that fingers, sex toys, and penises simply can’t provide.
It doesn't hurt to study this subject; it may make all the difference in kick-starting your sexual bliss!