No, not sex with a prison guard, but a position where the Receiver is held more firmly, subjected to the deep penetration thrusts of the Giver.
Free Love is actually about objecting to the strict definition of being bound under the confines of rules, established by society of the time, not about multiple sexual partners.
It has been noted in many societies, dating back before Christ.
The term itself, is believed to have been coined in the 19th Century, as a form of objection to state regulation and church interference in the affairs of couples.
This is basically done in a standing position.
The Receiver (one being penetrated) bends over at the waist.
Their legs are slightly spread apart.
The Giver (one doing the penetrating) moves in to drive their penis into the upraised bottom.
Usually his/her legs are spread just slightly further than the Receiver's legs.
With the Receiver bent over, the head lower than their groin, the Giver grabs hold of the arms, at the wrist.
The Receiver can also grab hold of the Giver's wrists, to insure a tight clasp, almost as if they were handcuffed together.
As the Giver moves in, to penetrate, they pull the arms taut, keeping them extended, with no bending at the elbows.
This is a less intimate position, but allows for deeper penetration, and pleasure.
Height differences can make this an uncomfortable position for the taller person.
Squatting more, will allow for proper penetration, if the Receiver is considerably shorter, however it would be better to have them stand on something substantial, to avoid those burning quads, that would result from this squatting.