Police were alerted to the man's butchered balls when he arrived at a nearby hospital and told police his tale of woe.
The victim told investigators that his ordeal began when he met Allen on a web site named The Eunuchmaker, with Allen claiming 15 years experience in surgery.
The pair arranged for surgery to take place on October 12 and the victim travelled to Oklahoma from his Virginia home, The Smoking Gun reported.
The victim reported being fully conscious as he was emasculated, receiving only local anaesthetic.
As he lay bleeding on the makeshift table, Allen reportedly told his victim that he was a cannibal and was going to consume the body parts.
Court records show that the victim told police Allen claimed to have "six more clients on the way to have the same operation," and that he "had a freezer with body parts."
Allen also allegedly shared that he "worked on someone that he described as crazy and that he left the male opened up to die overnight."
When he was still bleeding the morning after the surgery, the victim asked for help, only to be told: "No ER, no morgue".
The victim told police that after Allen relented and agreed to drive him to hospital he told him that his body would be dumped in the woods if he died en route.
Allen and Gates were eventually arrested when they went back to the hospital to check on their patient.
A subsequent search of their home uncovered pill bottles, syringes, medications and a cauterisation tool.
Cops also found restraint straps, a bloodstained doggy pad, a blue plastic medical sheet with a needle and small string, an adult nappy... and a plastic zip lock in the deep freeze containing what appeared to be testicles.
Allen and Gates were arrested and held on a US$295,000 ($314,600) bond, charged with conspiracy to commit unlicensed surgery, performing unlicensed surgery, maiming and assault and battery with a dangerous weapon.
"I can't say it's cult activity," Le Flore County Sheriff Rodney Derryberry told media.
"It is something that we have never in my career run across in this part of the country.
"It is borderline some type of activity... We know there's a lot of rumours out there but at this time there's no danger to the public."