Turns out whatever alien or supernatural entity wasn't looking to closely at who they gave the sex machine to, because they dropped it in a war zone. As in the recipient was inside a cramped tank and the Sex Machine ended up bouncing off the tank and in front of the tank's treads. The Sex Machine was durable enough to not break under that much weight, but it wasn't looking the best... Then some grenades and canon fire came which made it spark a bit... Then the bombings came where some cracks finally were forming making it start to malfunction... And then some idiot decided to use the tactical nuke, and that finally did the Sex Machine in. Sadly nothing sexy happened on that battlefield as everything was effectively atomized and dead, but the infinite energy and sexy energies were unleashed upon the world. Radiating from where the Sex Machine originally broke it's ability to change two living organisms and make them fuck spread out all over the world and even a few good miles outside of the atmosphere. The energy field stopped there, but with the infinite sex energy being infinite the energy field wasn't dissipating either.
With the sex energy being aimless it just saturated living organisms waiting for two of them to get close enough to generate a "static shock" which would trigger what would soon be known as "Sex Time". Since the energy just stuck to organisms the range would only ever increase till Sex Time struck. The Temporary/Permanent and Fertile/Infertile settings were seemingly randomly, although near the start many people were hesitant to call them truly random.
An interesting movement that came out of this was the "Fuck animals" movement... or movements. There was the "Fuck off animals" movement who were a bunch of people who feared permanently being turned into an animal with no guarantee of ever becoming human again. Especially when it came to insects who may have only a day or so to live. Then there was the "Fucking animals" movement where many people were embracing the animal fucking to get a better understanding of how different animals felt and perceived the world... It also had a lot of furries, animal-kin, people who didn't think you could get rid of all animals from most of the world, and people who believed the permanent transformations were influenced by your subconscious.
This new energy field came out of literally no where and would take the scientific community awhile to figure out how to track the energy since it didn't seem to affect inanimate objects at all, and then how to safely get to the broken sex machine as it was in the middle of a nuke site. At that point society had changed enough to revolve a bit around "Sex Time" and then the planet as a whole had to ask whether or not they should just fire the thing into space or just keep it on earth.