More than 250 people have pleasured themselves for charity today in Britain's first "Masturbate-athon".
Participants from all over the UK queued outside a converted photographic studio in Clerkenwell, central London, to take part in the controversial event.
Organised with the help of sexual health agency Marie Stopes International, it aimed to raise awareness of safe sex.
Event organiser Tony Kerridge had expected the event to attract protesters.
But he was relieved when only one peaceful campaigner, armed with a small placard, arrived.
Participant Neil Crawforth, 28, left his wife at their home in Cambridge while he came to do his bit for charity.
"I'm not a good swimmer and I can't run very far, but this is something I can do for charity," the software engineer said.
Mr Crawforth said he had managed to raise £50 through sponsorship - money that will go towards sexual health charity Terrence Higgins Trust.
Mr Crawforth, who described himself as "shy", added: "I do not like to talk to people very much, but I compensate by being an exhibitionist."
Filmed by Channel Four as part of a series of shows dubbed Wank Week, the Masturbate-athon is the first event of its kind in Europe having been exported from the US.
Protester Matthew Bull, 34, said: "I'm offended by the whole thing, not the act itself, but it being such a public event.
"As an Islington resident, I was not asked whether I wanted this in my backyard. I feel it is wrong and should not be accepted."
Participant Hal Musazlioglus disagreed. He said: "It is masturbating for a good cause. It's a fun thing to do and isn't hurting anyone. We are not doing it in front of anyone. It is in a building."
Inside, there were a number of rooms. Each decked out with comfy Moroccan-style cushions.
There were separate areas for men and women, a mixed room and an exhibition area for those who didn't mind being filmed.
Page 3 girl and pornography star Rebecca Smyth, 26, positioned herself in the exhibition room.
She said: "It is not that unusual for me to do this. I'm not nervous about it at all."
Organisers hope the event will stamp out the "Tabooness" of the subject of masturbation and encourage young people to use it as an alternative to unprotected sex.
Mr Kerridge added: "With penetrative sex, if it is unprotected we have the risk of STDs, unwanted pregnancies and most worrying AIDS.
"We want to get the public talking about masturbation as one of several alternatives to penetrative sex."
