It is not uncommon for women to achieve multiple orgasms for the first time in their sexual history using dildos or vibrators. But licking is only one of the pleasures involved in cunnilingus. Your moist lips and mouth are capable of creating a uniquely subtle range of sensations. Sucking your partner's clitoris, nuzzling her labia and penetrating her vagina with your tongue or fingers can all enhance the experience of oral sex. As with any sexual activity, the same strokes won't work for all folks and the same woman might prefer different types of stimulation depending on how aroused she is.
Many women enjoy having the whole vulva licked, from pubic bone to perineum.
Pay attention to the sensitive area around the urethra. You can insert your tongue in your partner's vagina, though obviously the average tongue will only go so deep. Most women would rather have their external genitalia tongued. Generally, it's easier to use a finger or dildo for penetration during oral sex. Bear in mind that as your partner approaches orgasm, she'll probably appreciate it if you maintain a steady stimulation up to and through her orgasm.