Personal Column: 'I go with gay strangers. We have our own code'

The first time a friend took me "up the Heath", cruising in the woods at the top of London's Hampstead Heath, I was terrified and turned on in equal measure. Being summer, it was still quite light, but most people have had a lifetime of being warned about men lurking in the woods - and here I was taking two buses to get to them.

Going "up the Heath" is a bit of a rite of passage for many gay men, often the first time you've done the anonymous sex thing, and it's something you are usually initiated into by a friend who already goes up there.

Mine steered me down the steep path behind the pub car park to the main drag, a path through the trees about the size of a main road, lined not with lamp posts or speed cameras, but with men sitting on every available horizontal plane, leaning against every tree. They were smoking, ignoring their dogs (a lot of "straight" men use dogs as excuses for being here), giving lots of eye-contact and, if they liked the look of you, provocatively stroking the front of their jeans or tracksuits.

The men who come here are all ages, from teenage to old age, done out in anything from chavvy sportswear to walking boots, shorts and jeans with the odd bit of fetishwear thrown in. After dark there can even be a naked man walking about, pale and ghostly. And the pace is slow. So slow it can look like that scene from Night of the Living Dead when all the zombies emerge from out of the darkness.

This is what it's like if you go on a warm summer night. In winter it's still busy (Christmas Day is especially popular), but you have to scale the steep slope behind the car park in pitch blackness, sliding in the mud: in London gay circles, the sudden appearance of muddy shoes in a hallway is the instantly recognised sign that someone's been out cruising, by the way. In winter, the presence of "trade" (an old-fashioned but still quite acceptable term for available men) is picked out by the little glow of their cigarette ends or a glimpse of white sock.

There's a lot of walking around involved in cruising. On the Heath, there's a sort of circuit and you can go round on your own or with a friend, though loud talking is frowned on as it seems to break the spell. Alternatively, you can sit on the sidelines and watch the circuit go past you.

When you see someone you like, it's a case of eye-contact, move on, come back for more eye contact. There are very strict unspoken rules of respect in a cruising situation: it's simply not done to force your attentions on anyone who's not giving welcome signals.

When you have established that you're both interested, you move in. Again, talking is not encouraged. A raised eyebrow, a half-smile as you move in to touch a buttock, maybe, or the front of the jeans. If you've got it all wrong, two little pats on your arm politely get the "not interested" message over.

Just because this is as casual as sex can possibly be, that doesn't mean feelings aren't involved. You can still feel rejected if you get the brush-off, you can still feel a pang if a guy you have had your eye on gets off with someone else. Obviously, you're over it before you've left the Heath, but it's not entirely without emotion.

When you do meet someone who's interested, you'll usually go off to one of the many little secluded areas among the bushes (authorities who want to stamp out this sort of behaviour always start by cutting down the bushes) and then go through the same sequence of events as you'd go through with any partner: you'll go through the "bases" from kissing, to caressing, to putting your hands inside clothes, to undoing those clothes, and so on.

There is no taboo in gay cruising. Everything that can be done, can be done here, the resulting litter of tissues and condoms quite rightly angering local daytime users of these woods. If you like an audience, all you really have to do is make some noise and a crowd of men will appear to provide it. Some couples like to be watched and not touched, others like a general free-for-all: the same two- taps rule functions well in establishing what you want here.

Anyone wondering what George Michael was thinking of, going with a much older, much less attractive man the other week, should certainly not assume that he was representative of what is on offer on the Heath. Personally, I've had a gorgeous twentysomething male stripper, a 6ft 7in Croatian brute, dressed head-to-toe in leather, and pretty much everything in between.

And if you were surprised that George should be up there in the first place, you have to understand that apart from the complete relief from commitment that comes from having sex with someone you've not even spoken to, the excitement of doing it with other people around can be part of the fun.

It's not so much the risk of cruising in public that makes it exciting. The police, for example, seem not to worry about rounding up cruisers the way they once did.

But apart from the handful of cases such as Jody Dobrowski, murdered as he was cruising on Clapham Common, cruising is almost always safe, especially in the summer when the Heath can get borderline crowded. Besides, anyone you decide you'll go back with after meeting in a bar - gay or straight - can be much more of a danger behind closed doors.

As to whether it would be a surprise to come across George Michael while cruising, the Heath really is, like much of the gay scene, the most mixed of bags: lawyers get it on with barrow boys, multimillionaires with the unemployed - even celebrities with other celebrities.

John O'Brien's name has been changed