Benwa Balls
If you have a set of BenWa balls, place them in yourself and keep one of them held on your g-spot with your finger.
Use your other hand to then masturbate your clit while simultaniously moving the ball over your g-spot and applying a small amount of pressure there.
It is the most amazing orgasm that I have ever felt, and using a bit of good chick/chick porn makes it even better!