The court heard Gustavson, 46, had been involved in numerous extreme procedures, including filming the removal of male genitalia and posting the footage to a pay-per-view “eunuch maker” website.
The practice is linked to a subculture where men become “nullos”, short for genital nullification, by having their penis and testicles removed.
After cutting off Gustavson’s penis, Byrnes asked for a copy of the film and was heard saying: “Well that’s one off the bucket list. I never expected that one.”
Caroline Carberry KC, prosecuting, said messages between the men spanning four years had been found on Gustavson’s mobile phone and the defendants were among 10 people charged with taking part in extreme body modification.
Byrnes had initially been hired by Gustavson for escort services and in December 2016 he agreed to remove Gustavson’s penis for a fee of £500, saying he was in debt.
Texting Gustavson, he said: “I have no issue with it but won’t you loose (sic) a lot of blood… like nearly die.” He also expressed concern that he might get into trouble.
But Gustavson explained he would have a local anaesthetic and receive instructions about what to do.
On February 18, the procedure took place and was recorded from two angles.
Afterwards, Gustavson called 999 and told the operator: “I tried to do some surgery on my c---”, the court was told.
He was treated in hospital and discharged after a couple of days with a referral to a psychiatric unit for assessment.
Carberry told the court it had been a “life-threatening procedure”.
When Byrnes did not receive payment, he threatened to go to the police.
Following his arrest in 2022, Byrnes admitted what he had done, saying he was in financial difficulty and had thrown up on the way home afterwards.
Gustavson previously admitted charges including conspiracy to commit grievous bodily harm and will be sentenced with others on March 4 and 5.
Mitigating for Byrnes, Lisa Bald said he had suffered trauma during his Catholic upbringing in Ireland that set him on a path to drug addiction and desperation. Ms Bald added that he was “appalled and ashamed” by what he did in 2017.
Byrnes wept in court as his barrister said his mother was suffering from terminal cancer and appealed for a non-custodial sentence.
Mitigating for Arnold, Neil Griffin, described him as a compassionate, gentle, mild-mannered and respectful nurse. He committed the offences while in the grip of “hypermania” brought on by bipolar disorder.
Griffin said: “He is most unlikely ever again to engage in fantasies and the behaviour that he was prone to four years ago.”
Judge Mark Lucraft KC adjourned the sentencing until January 15, telling the defendants that his “mind was not made up” on whether to hand them jail terms.
He said: “This case is unique. It is quite unlike any other case I have dealt with.”
