A hard butt pounding sex position, that requires some flexibility and stamina, and a nice sized dick. The thrusting is like a pile driver, a relentless constant pounding of a stationary object, by a moving one.
This is how to get a real workout, and not for the faint of heart.
To begin with, this position requires a bit of contortion from the Receiver (the one being penetrated).
The Receiver lays on their back.
They then raise their lower back and legs upwards, and over.
The legs are spread apart and are brought forward, to rest just beyond the head of the Receiver. (like I said, you need to be a contortionist or expert in Yoga positions).
By placing both hands, below the upraised hips, can afford some support to your upraised body.
The Giver (the one doing the penetrating) needs to squat down, and penetrate the exposed crotch.
Experiment with the angle, by guiding the penis with your hand, or in your positioning of your body, in relation to your partner's exposed area.
Both partners are facing the same way, as a rule.
The Giver is more or less, sitting on the upraised buttocks, while performing.
Generally speaking, the Giver moves up and down, to provide the necessary thrusting action.
Once penetrated, the motion is generally hard sharp thrusting movements, but care needs to be exercised to avoid changing the angle to a less than comfortable one.
In this position, the penis is generally pointing downwards, in order to make penetration.
Care must be taken to not endanger the penis, during the rapid thrusting motion, while in this position.
Not many can manage this position, due to the need for such flexibility on the part of the Receiver.
The quicker the up and down thrusting is, the more strain is placed on both the penis, and the Receiver's back.
Don't get carried away.