Well, now you're there. She wants to cum and she wants to cum NOW. This is NOT the time to whisper in her ear "I'd really like it if you'd suck my dick." This will leave you with blue balls and her masturbating at home, thinking about some OTHER guy. But you're not ready to go down on her. What else is there to do? Take her in your left arm (right arm for you lefties out there) and hold her close. As she becomes ready, slip your hand into her panties. And, guys, make sure you have manicured fingernails. Nothing will turn a girl off more than the feel of a hang-nail dragging across her most sensitive body parts. Also be sure your hands are clean. Those spicy tacos you ate before you picked her up will ruin your chances of getting this far ever again. So, hands washed and manicured, you're ready to go. With your right hand (left for the lefties, of course), slide down between her legs until you find a warm, moist slit. You are now hopefully touching her vulva, trying to get your fingers between her labia. Do this cautiously, as some women will have a tendency to try to close their legs if you are going too fast. Once you slide your fingers past her labia, you should feel the vaginal opening as wet and hot. If it is not, you will be best suited to remove your hand and lick your fingers.
Now that a bit of lubrication has been established, insert your finger into her vagina. Just one to start. No woman likes to be bombarded by too many fingers stretching her too quickly. If you feel that there is plenty of room for another finger, feel free to attempt it, but if she winces, stick to just one finger. Slowly insert and withdraw your finger(s), letting her get wetter and hotter while you continue to kiss/suck/nibble on her special spot. When she begins to moan, you have been given a cue to move on.
At this point, the move you make will set the example for how your sexual relationship will continue. Remember, chivalry is something that most women consider to be a dead art. Prover her wrong. Remove your now moistened finger and place on her clitoral hood. Trust me, it feels like a button. Hopefully you were smart enough to have used your middle finger to have stimulated her already. If not, skip back and insert your middle finger to get it moistened as well. I say this because most people can place more pressure on the index finger than on the middle finger, which will prove beneficial in just a few minutes. Begin to slowly massage her clitoris with your middle finger. Notice how she writhes in your free arm. Do not, under any circumstance, remove this arm from around her shoulders/body. No matter what she tells you, she likes the closeness of being held. It makes her feel more loved. Continue kissing/sucking/nibbling her special spot. You'll know when it's time to stop. Gently increase your speed on her clitoris, applying just a little more pressure, but not enough to hurt yourself or make her uncomfortable. Flexibility will be a big help by now. She should be getting close and, with any luck, beginning to buck her hips.
If she's vocal, you'll know when the time is right. If she isn't vocal, you'll have to read her face. As she begins to enter her climax, swiftly change fingers, switching now to your index finger. Remember what I said about pressure? You'll understand in just a moment. By now, she'll probably be ready for you to break your lips away from her and let her enjoy what is happening. Pull her as close to your body as you can and apply a decent amount of pressure to her clitoris. If you're skilled enough, you should be able to pull her clitoral hood over her clitoris without missing a beat. Rub her bare clitoris with speed and pressure, allowing her to cum on your hand. Continue with this pressure and speed until she tells you to stop, clasps her legs, or, if you're a real stud, passes out. Slow your movement and lessen the pressure, but DO NOT STOP. Stopping will only frustrate her due to the orgasm ending TOO quickly. Resume your previous kissing/sucking/nibbling. She will probably be panting and gasping for air. If you love her, tell her so. If not, don't lie to her. Women can be emotionally vulnerable after an orgasm. And hopefully you've just given her the best orgasm of her life.
Repeat as needed. An estimated 98% of women do not orgasm through penetration alone. After she has allowed you to make love with her, show her that you care about her needs as well and give her a manual orgasm. You'll have her hooked.