Kevin Miles, a nurse at London's newest clinic for sexual health, is delicately scraping swabs of my urethral tissue with a 6in plastic baton. A swab for gonorrhoea. A swab for non-specific urethritis. A final swab for chlamydia. It's the last which brings tears to my eyes.
'It's the cotton-wool that does it, Kevin says. 'It can feel like tiny little teeth. Some people don't feel a thing. Others faint. I have even been punched in the face.'
A rectal examination follows, inevitably undignified, but mercifully swift. Then samples of urine and blood, screening for hepatitis and syphilis.
This is just a regular check-up. The kind that many professionals would like patients to undergo every six to 12 months. Just like visiting the dentist.
The Mortimer Market Centre for Sexual Health opened on 1 September. If patient projections of between 80,000 and 100,000 a year are correct it will be the largest clinic of its kind in the country - in fact the biggest 'clap' clinic in Europe.
Actually Mortimer Market is not a 'clinic'. It is a Centre. Genito-urinary medicine has traditionally been the Cinderella of the medical profession, a basement service, tucked down alleyways, found only at the end of dark corridors. Not any more.
The new building is all curves and carpets, atriums and apple blossom walls. The feeling is almost corporate, the result of the largest capital investment (about pounds 4m) by Camden and Islington Health Service Trust since its inception last year.
Anyone who decides to walk through the sliding door at Mortimer is entitled to treatment, a policy enshrined by the Venereal Diseases Act of 1917. There is no residency requirement. Confidentiality is sacrosanct - even the police cannot access records.
Mortimer Market is the product of five years of planning meetings, operational policy committees and the eventual merger of James Pringle House and the Univeristy College Hospital clinic.
The male and female outpatients have been joined by an expanded HIV unit, a dental clinic, a new colposcopy suite (for cervical smears), a psychosexual service (offering counselling and group sessions for herpes sufferers and 'sex addicts') and an academic department.
Unlike most areas of medcine, many of the academics see patients at the clinic. 'This contact is vital,' explains Professor Ian Weller.
'Over the last six or seven years there has been an enormous growth in this area. This has been brought about largely because of HIV. The speciality has attracted a lot of talented young doctors.'
Out of the tens of thousands of patients seen every year at the former James Pringle clinic, there has always been a slight imbalance in favour of women - more than 55 per cent of all appointments. Women tend to visit the clinic when they start a new relationship, or come for cervical smears. Around a quarter leave with no reported infection.
Lily is 27. She originally went to the clinic with a friend, and subsequently discovered her boyfriend was HIV positive. She was diagnosed as positive in 1990.
'There has definitely been a change in attitudes to sexual health. Certainly I find it a lot more easy to talk about it with my friends. I always felt I was being treated with dignity and respect. Mortimer will have the same staff. The nice new surroundings can only help.'
Almost half of the men who visited James Pringle were identified as homosexual; the proportion was slightly lower at UCH, where patients tended to be students, commuters or local residents.
This and a high rate of reinfection among some female patients suggests there is a group of potential patients that still finds it very hard to approach the clinic - heterosexual men, opines one health adviser. 'They are the greatest threat to heterosexual women's sexual health.'
Dr Allason-Jones believes he knows why: 'Many men still come here having heard the umbrella myth. They think there is some umbrella swab we insert down the urethra, which will then open up and dragged out. I don't know where this idea comes from.'
With the high percentage of homosexual men expected to use its services, Mortimer is very conscious of coming across as 'straight-friendly'. 'Whether right or wrong, a lot of straight men think the clinic is doubly-stigmatised - not only might people think they have venereal disease, they might also think they are queer,' acknowledges John Howson, the patient services manager.
Slides, samples and swabs from my check-up are packed in a grey cylinder and sucked up a vacuum shaft to the microbiology lab on the third floor. The syphilis sample is laid in agar jelly and placed in what looks like a small microwave oven to culture for a week. Other samples are smudged onto slides andcarefully examined under microscopes.
Back on the ground floor Dr Mala Maini sits in her large consulting room, searching for a stapler to clip my notes together. 'How was it? Not too uncomfortable I hope,' she asks. On her desk are the results of three of my tests (there is a week's wait for the others): gonorrhoea, non-specific urethritis and chlamydia: Negative. Negative. Positive. But not necessarily in that order.
'Oh, not to worry,' chirps Dr Miles. 'Just think of it as a sign of virility.'
The Mortimer Market Centre for Sexual Health, Mortimer Market, off Capper Street WC1 (off Tottenham Court Rd).
Names of patients have been changed.