You've got to understand, I've been under a great deal of stress recently. Why else would I be paying for a massage on a street corner in Soho - just £5 for full "Chinese" - knowing that the police might find me at any moment with my clothes in disarray? What if someone recognises me? What would they think? Then again, perhaps the risk of being discovered gives this sensation an added frisson. The idea that tourists are passing by within a few inches of me and - I'll call him "Jim", since that was the transparently phoney name he gave me. Well, let them sneer if they want to, let the police do their worst. If it's a crime to help a young man through college, a young man who's not afraid to offer a little relief to an over-stretched professional person, then go ahead and read me the rights.
It's not a crime, actually, or rather it doesn't appear to be. They're a bit of a grey area, the pavement massages of London's red light district.
If it's not on your regular itinerary, you may be as surprised as I was to learn that pummelling and kneading is the latest trick that they're turning down there. Since the summer, the weekend visitor to the West End has encountered not only the familiar underdressed girls on the doors of clubs, but a line of Chinese men standing over stools and dispensing rubdowns like seconds at a tag Kung Fu bout.
A police officer in Leicester Square said that the masseurs were liable to be moved on if they were judged to be blocking the highway. "But you're not about to nick them?" He wasn't, he said.
The place to see them is among the restaurants of Chinatown, where the waiters smoke and gamble between sittings and racks of tanned, leathery birds fill the windows. The first time I came across the masseurs they were in line behind their stools, like barbers. But where were their scissors and combs, their mirrors and razors; where the foamy lather and steaming towels?
It was only when I drew closer, and saw that passers-by were coming forward to take a seat and accept a gentle battering, that I realised that I had stumbled upon a remarkable service.
Jim couldn't have been more gentle - to begin with. After I removed my jacket, he began stroking my eyelids as though he was tenderly wiping the sleep from my eyes. But now he's cupping his hands over my ears until they pop, and tugging at them as though he's a prop forward toying with me, letting me know what he'll do the next time the ref's back is turned.
The ornate Chinese gates off Shaftesbury Avenue and, beyond them, the Post Office Tower swim before my eyes. Jim's from Beijing, he tells me. He's wearing jeans and trainers and spectacles. Patting and thumbing my scalp, he could be a backstreet trichologist, disguising a cowlick which has failed to take. In fact, he's a student of banking and is following a course in London. Jim dextrously addresses my shoulders and I feel myself unwind; I close my eyes.
Did I mention I've been under a great deal of stress? In my head, I replay every fretful moment of my Tube journey from north London; before that, there was the agony of trying to find something to go with my new salmon shirt. Talk about tense!
I sense Jim tugging my fingers as though he's turning a pair of rubber gloves the right way out. He taps my wrist. "Watch!" he exclaims delightedly, and taps my wrist again. I think "Watch what?" and open my eyes. Of course: my watch. A gift from a friend in Hong Kong some years ago, the fully-jewelled action shows a still-vital Deng Xiaoping waving the British off the premises. Jim is so pleased by this discovery that he calls several of the other masseurs around to wonder at it.
One of them is Abelardo Guinto, who says he's half-Chinese, half-Filipino. Mr Guinto regards his colleagues with the resignation of a bespoke tailor in a flea market. "Some of these guys are not for real - they're amateurs," he says. "But I'm a mobile terrorist."
At least, that's what I think he says; actually, Mr Guinto has a mobile therapy business. He tells me that he learnt the ancient skills of shiatsu in his native Manila, where they're practised in big hotels and hairdressers' and private homes.
But the street massage business began in London as recently as June, with only a couple of people offering the service. Why has it caught on here?
"Why? People are very stressful," says Mr Guinto. "You can see this. It's cold today but people still want to sit on the street to have a massage."
I think of a scene in Martin Amis's novel Money - possibly the only scene not pored over by critics - in which the yuppie pornographer Fielding Goodney is predicting the next big thing in rackets; in the "addiction line", as he puts it.
"'Cuddles,' said Fielding Goodney. 'Cuddling up. Two people lying down and generating warmth and safety. Now how do we market this? A how-to book? A video? Night shirts? A cuddle studio, with cuddle hostesses? Think about it, Slick. There are millions and millions of dollars out there somewhere in cuddles.'"
Fifteen years after Money was published, it seems everyone needs that human touch, as Amis's anti-hero, John Self, might have put it. The cuddles market is still in its infancy. Indeed, it's debatable whether having your upper body manipulated counts as a cuddle at all, strictly speaking, though it clearly belongs to the family of embraces.
In Chinatown, they haven't yet solved the marketing problem posed by Fielding Goodney. For a start, everyone's charging the same - a fiver. Not even a high-end practitioner such as Mr Guinto is bucking the trend, to reflect his painstakingly acquired massage chops. What marketing there is amounts to a bunch of men (and they do all appear to be men) barking their business beneath the neon sign of the Dumpling Inn - "Hello Lady. Massage! Come on! Come on!" - and gesticulating towards their stools.
These aside, there is nothing by way of kit or accessories, in contrast to other branches of the stress industry. There are no float tanks or aromatherapy oils or acu- puncture needles. Endearingly, there is an absence of merchandising and spin-offs.
I like the lack of technology. This isn't an "experience" or a world for which you queue. It's more like that cherished British folk memory or myth: making your own entertainment.
But how will Chinatown's touchy-feely business develop?
A sandy-haired visitor from Brisbane called Mac Addis has just taken advantage of the service. He's waggling his neck as tentatively as a tortoise in spring: "Do I feel like a new man? I wouldn't be that extreme, but they do have an intriguing way of massaging your back."
He tells me that the spectacle we're witnessing in Soho is a common sight in his home town. "Massage has taken off in a big way on a Sunday morning."
If it becomes established in London, a practitioner such as Mr Guinto may be able to open up a competitive advantage over his neighbours.
"I give aftercare advice," he says, reading my thought. "I tell people to drink plenty of water and keep warm. They shouldn't smoke for about an hour after massage. I say 'eat less - don't indulge yourself!'" You'd be comfortable entrusting your collarbone into Mr Guinto's hands.
Perhaps I've seen too many kick-boxing films, but I'd probably not offer my unguarded kidneys to the man next to him, who has the broken nose of a stunt-double from a John Wood movie. He has a cigarette on the go, and another behind his ear. You're much less likely to get a ricked neck, Mr Guinto implies, if his type of trained and experienced masseur corners the market.
There's something in this, no doubt, though it would spell the end for the low-tech, communal, practically Hogarthian, atmosphere of the Chinatown rubdown.
Before you know it, there would be salons and smocked assistants, all after a piece of the million-dollar cuddles scene. There would be videos and nightshirts.
Seriously, this could be the next big thing. Who knows whom you could end up rubbing shoulders with?
Stephen Smith unwinds by reporting for "Channel 4 News". His travels in restful Colombia appear in "Cocaine Train" (Little, Brown £17)