1) Place one hand as if inside of her....
2) Raise just the ring and middle fingers...
3) Place the center of the palm of your hand over both the middle and ring fingertips.
4) Imagine the woman's body between your palm and fingers... find the movement of your fingers she responds to the best, and do that, trying to rub the palm of your hand from inside of her. The added pressure increases the sensation for her.
5) Add woman.
(It works best when she's on her back, you're on your knees kneeling beside her)