The book "Sexual Secrets" by Nik Douglas and Penny Slinger describes this position thus: "The man lies on his back with both legs spread and extended. The woman squats over him, straddling his thighs and facing him. With her feet resting on the bed, she moves over him, delicately and vigorously, supporting herself with her hands. She plays upon his Positive Peak with her Jade Gate."

That's an excellent beginning. Now let's add the detail. The "woman superior" positions are excellent for G-spot stimulation. A woman can subtly move her body to angle her pelvis and Yoni (Sanskrit for Vagina) just so for maximum stimulation.