SIX men have told the jury in the trial of Graham Dwyer that they were in contact with Elaine O'Hara through adult members' websites, with two saying they had sexual relations with her.
The six were all members of sites catering for people interested in alternative sexual lifestyles, and four never met Ms O'Hara in person.
However, one of the men who had sexual relations with Ms O'Hara said her interests were "extreme".
The six were giving evidence in the trial of Mr Dwyer (42), an architect of Kerrymount Close, Foxrock, who is pleading not guilty to the murder of Ms O'Hara (36) at Killakee, Rathfarnham on August 22, 2012.
Her remains were found by a dog walker in undergrowth in the Dublin mountains on September 13, 2013.
Robert Cullen Jones told the jury he met Ms O'Hara through the website www.alt.com around March 2011 and they started texting before meeting up the following month.
Ms O'Hara's profile was 'Helpmelearn 36/F' and his username was 'Dublin_master'.
He said Ms O'Hara "would have described herself as submissive".
Speaking softy and slowly in the packed courtroom, Mr Cullen Jones told Sean Guerin SC, prosecuting, that the pair eventually met for coffee in Dundrum shopping centre, before going back to Ms O'Hara's apartment in Belarmaine Plaza, Stepaside.
They had "sexual relations", Mr Guerin said.
"That's right," Mr Cullen Jones said.
The court heard Ms O'Hara also told Mr Cullen Jones about her interests and previous relations, and that she liked being tied up.
However, they did not do that.
They met again for coffee in May 2012 but contact fizzled out and he deleted her phone number.
While Mr Cullen Jones was in Ms O'Hara's apartment, she showed him some "sexual paraphernalia".
"I remember a pair of handcuffs, she had them in a drawer by the side of her bed," he said.
He saw a number of different vibrators.
He gave gardai his laptop and swabs for the purpose of DNA analysis.
The jury heard Mr Cullen Jones had been shown a number of photographs by gardai.
"I remember seeing one of the handcuffs and it could well have been the same one I saw when I was at the apartment but I couldn't be certain," Mr Cullen Jones told the court.
He was shown a picture of two sets of cuffs with a linking rusty chain and Mr Guerin asked if he had told gardai he was of the view that this was not what he had seen.
He replied that he would have seen something "very like the top two cuffs" but not the rest.
"In terms of what you discussed with Ms O'Hara, I think what she told you was that she had a fantasy to engage in sexual games, as in bondage or restraint where she would be tied up and submissive, giving up control of her situation," Mr Guerin said.
"That is correct, yes," Mr Cullen Jones added.
This was the only fantasy that she discussed with him.
The court heard that expressions cropped up on the alt.com website site like "breath play" involving restricting someone's breath or asphyxiation.
Other were "wax play" involving candles and "knife play" which was "like cutting", Mr Cullen Jones explained.
A second man, Mark Guerin, met Ms O'Hara twice at her home four to five years ago and she laid out restraints on a bed on both occasions, but had sexual relations once.
Mr Guerin said her interests had involved "restraint, blood-letting, humiliation and degradation" but he was "more into light kink".
Mr Guerin's username on www.alt.com was 'time2killindublin'.
On the first occasion they met at Ardmeen Lodge, Blackrock, Ms O'Hara placed restraints on her bed.
"From being here today, I recognise the cuffs and chains from the photograph that was shown earlier," he said. "If not that, something similar."
"We talked quite a bit," he said. "She was quite nervous and she spoke about her past and her situation."
They did not have sexual relations then.
They met again at her apartment in Stepaside and she was in "very good form", he said.
She again laid out some things on the bed including restraints, he said.
She was in a "lighter mood" on this occasion and they had sexual relations.
Other men agreed they must have made contact with Ms O'Hara through adult websites, but had little recollection of it.
Gardai contacted three after their numbers were found on Ms O'Hara's phone.
Patrick McGurk said he had been a member of CollarMe.com but did not remember Ms O'Hara and never met her.
Alt.com member, Bernard Grealy, said he had been in touch with a woman through private messaging in 2011, who he now believes was Ms O'Hara.
Sean Byrne, a member of fetlife.com and alt.com agreed it was "more than likely" that he contacted Ms O'Hara, although they never met.
The sixth man, Kurt Ronnhuist agreed gardai contacted him about instant chat messages between him and Ms O'Hara on alt.com in December 2010. He also never met her.