A prostitute lured a school assistant to a city flat before her boyfriend held a knife to his neck.
Donna Houston, 36, and 42-year-old Allan Blues admitted ambushing the former Morgan Academy employee while he was naked on a couch.
The pair have been warned they face a “substantial” prison sentence after pleading guilty during their trial at Dundee Sheriff Court.
A third accused, Lindsay Hutcheson, had not guilty pleas accepted by the Crown.
The victim told jurors he had contacted a woman on a website called “Helen”, actually Houston, and agreed to pay £50 to have sex with her.
Shortly after arriving at the flat on Baldovan Terrace, Houston took a photo of him naked before Blues burst into the room and brandished a knife while threatening to cut off his genitals.
He was later taken to a nearby cash machine and forced to hand over £150 from his account.
Following their guilty pleas, Sheriff Alastair Brown said: “In any view this is an extremely unpleasant and very serious crime involving what appears to be a deliberate plan to lure a man, relying on what he described as a weakness of his, and when he was at a complete disadvantage.
“The sentence which I am at present considering is close to the limit of my powers because this is a very serious offence.
“I make you no promises but to consider very carefully the terms of the report which I am going to order.”
The victim previously told jurors he thought he was going to die when the kitchen knife was held to his neck.
He said: “A female answered the door and I went into the living room – she suggested I take off my clothes and I did. She wanted to take a picture of me.
“She said it was for her profile but I pressed her to delete it.
“A guy came into the room while I was on the sofa. He said ‘I’m going to cut your penis off.’ I was terrified. I thought I might die.”
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Houston, of Transform, Soapwork Lane and Blues, of Baldovan Terrace, admitted assaulting and robbing the man of a wallet, money and other items on February 28 last year.
The pair were cleared of a second charge of robbing another man at the same flat in June last year.
Sentence was deferred for social work reports until next month and the pair were remanded in custody.
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