A strength needed sex position, where one holds the legs up, while penetrating the other, who can wind up moving a bit, with each hard thrust.
Better have some strong arm strength for this one, both of you.
The Receiver (the one being penetrated) is on all fours, to begin with.
The Giver (the one doing the penetrating) will need to pick up the legs of the Receiver, just like one did when they had 'wheelbarrow races' at picnics.
Taking a firm hold of the legs, near the thighs, the Giver steps inside the upraised legs of the Receiver.
Adjusting their grip, and positioning of hands, they then proceed to penetrate the exposed rear of the Receiver.
The weight is being born by both parties, by their arm strength.
Keep in mind, each thrust will add to the force being felt by the Receiver in their arms.
The Giver may have to adjust their height, or/and hold, in order to effect good penetration.
While thrusting forward, the Giver should be pulling back on the legs, to make the penetration even more powerful, more rapid.
Practice (Associated Acts):
Adding a third partner, can lead to some interesting sex.
The third person, would be an ideal Receiver, for a nice blowjob.
In addition, they could provide a good means of providing stability, not to mention relief for the Giver by being able to switch positions with them.
Too much thrusting, or too hard of a thrust, can put the Receiver off balance, forcing them to either step forward, or worse, fall flat on their face.
Balancing the Receiver's legs on your own thighs, or hip area, may impede full penetration.
Holding the upraised legs further apart, can remedy that situation.