By now she should melting, you don't want to draw it out too long, or she will be driven completely crazy, and that's not the effect you're after. You want her to want it, but not so bad it hurts. Then Bury your face between her thighs, you won't want to attack it just yet, but being in position ahead of time doesn't hurt. A quick move to make it appear you are going to full on dive in will drive her NUTS... especially when you don't right away. Push your lips over hers and then just stop, don't move at all! Hold this for a few seconds, maybe 5 then do it again, but never actually sucking on the lips. This is a good finally to the teasing process. By now, unless you have ZERO skills she should be squirming like a fish out of water. It takes time to get it where she is truly in heaven by this point, don't give up if you can't figure it out, just keep at it