18. the Crab

The man is lying on his back. The woman rides him backwards and guides his lingam into her yoni. She then leans backwards, holding herself with her arms. She can pump her legs to make the up and down motions.

Plusses
The woman has full control of the movements and of the depth of penetration.
The man can freely caress her breasts with his hands.
The sensation of the woman's hair brushing against her partner's face is particularly pleasant for him.

Minuses
There is a risk of involuntary withdrawal if the woman's movements become too fast or uncontrolled.