'Then she says, "Tell me." I say, "I'll tell you upstairs," and I go over to the mama-san, a real hard-faced bitch, and give her four bucks. Then we go upstairs. Her name was Oy. She takes off her blouse, and she's got these fantastic knockers and this beautiful brown back. She says, "What you want?" I says, "Anything?" She says, "For five dollars – anything."

'I gives her a fin and she takes my clothes off and starts washing my process and asking me if I've got the clap. The washing sort of turns me on and I tell her to hurry up. So she turns off the light and pushes me back on the bed, and God I've never been gobbled like that in my life. Her tongue's whirling around and I'm practically fainting. But I pulled it out before I came. Now what? I had these oddball ideas and I just said the first thing that came into my head. "Turn over," I says. "I want to piss on you."

'"Okay," she said. Okay! She gets down on the bed and I knelt over her. But I couldn't do it – I don't think I really wanted to – so I started screwing her ass for all it was worth. I came and rolled her over and that's when I slid my hand up her thigh and touched the biggest process I've ever – Look, I don't want to ruin your dinner.'

i think I've heard that one before,' I said, as we passed down the train to the dining car.

'No, no,' said Tiger. 'You don't understand.'

We each had a Singha Beer. I ordered fried rice with prawns and mixed vegetables, and outside was the perfectly flat, unwrinkled Khorat Plateau. Tiger had been drinking whisky in the compartment and by the time the food came he looked a bit drunk; his face was flushed and even the scar on the top of his head was slightly rosy.

'You've heard the story, right? The girl that turns out to be a guy, right?' He began to eat. 'Well, this isn't the same story. Sure I panicked and she laughed – or he laughed. He says, "Don't you like girls?" and gives me a really horrible smile in the dark. I puts my clothes on -

I'm dying to get out of there. But downstairs in the bar I decide to have another beer. I sit down and Oy comes over again. He says, "You don't like me." I buys him another Pepsi and by then I'm kind of calm. "I like you," I says and – believe it or not – I give him a kiss on the cheek. I mean, don't get me wrong. This wasn't really a man – it was a girl with a prick! It was fantastic. You probably think I'm nuts – I know this sounds screwy -but if I go to Vientiane again I'll probably go over to the White Rose and if Oy is there I'll probably – yeah, I probably willV

Some time during the night, Tiger left the train. I woke to an empty compartment at six in the morning, and, snapping up the window shade, saw that we were moving quickly past black klongs to a city of temples and square buildings coloured pink by the sunrise. But the light was brief. It turned sickly, then dimmed to grey-ness, and we arrived shortly afterwards at Bangkok Station in a heavy rain.

When the American troops left Vietnam and all the Rest and Recreation programmes ended it was thought that Bangkok would collapse. Bangkok, a hugely preposterous city of temples and brothels, requires visitors. The heat, the traffic, the noise, the cost in this flattened anthill make it intolerable to live in; but Bangkok, whose discomfort seems a calculated discouragement to residents, is a city for transients. Bangkok had managed to maintain its massage-parlour economy without the soldiers, by advertising itself as a place where even the most diffident foreigner can get laid. So it prospers. After the early morning Floating Market Tour and the afternoon Temple Tour, comes the evening Casanova Tour. Patient couples, many of them very elderly, wearing yellow badges saying Orient Escapade, are herded off to sex shows, blue movies, or 'live shows' to put them in the mood for a visit later the same evening – if they're game – to a whorehouse or a massage parlour. As Calcutta smells of death and Bombay of money, Bangkok smells of sex, but this sexual aroma is mingled with the sharper whiffs of death and money.

Bangkok has an aspect of violation; you see it in the black jammed klongs, the impassable streets that are convulsed with traffic, and in the temples: every clumsy attempt to repair the latter seems to have been initiated by tourists rather than worshippers. There is a brisk trade in carvings and artifacts stolen from temples upcountry, and this rapacity – new to the once serene Thais – is encouraged by most of the resident foreigners. It is as if these expatriate farangs expect a kind of repayment for the misery of having to live in such an insufferable place. The Thais muddle along, as masseuses and marauders, but a month before I arrived several thousand Thai students (who described themselves rather curiously as 'revolutionary monarchists') marched on the police headquarters, brought down the government, and in the space of an afternoon managed to destroy seven fairly large buildings downtown. It was, like the patchy regilding of the recumbent Buddha, a popular violation, and now the street of gutted buildings is included in the Temple Tour: 'Over here you will see where our students burned -'

The railway station is not on any of the tours, which is a shame. It is one of the most carefully maintained buildings in Bangkok. A neat cool structure, with the shape and Ionic columns of a memorial gym at a wealthy American college, it was put up in 1916 by the Western-oriented King Rama V. The station is orderly and uncluttered, and, like the railway, it is run efficiently by men in khaki uniforms who are as fastidious as scoutmasters competing for good-conduct badges.

It was dark when the south-bound International Express (so called because it penetrated Malaysia to Butterworth) left the station. In the klongs Thai children were floating banana-leaf boats, with jasmine rigging and masts of flickering candles for the hoy Krathong festival. We rolled along under a full moon, which was the occasion for the festival, the lunar fluorescence mellowing the suburbs of Bangkok and giving to the Chao Phraya River a slippery sweetness that persisted until the wind changed. Fifteen minutes out of Thonburi, on the opposite bank – once the capital – the countryside and all its crickets rushed swiftly up to the train and we were swept with sighing grass.

Mr Thanoo, the aged traveller in my compartment, sat reading Colonel Sun, by Kingsley Amis. He said he had been saving it for the trip, and I didn't want to interrupt him in his reading. I went into the corridor. A Thai, about forty, with thinning hair and an engaging grin, said hello. He introduced himself: 'Call me Pensa-cola. It's not my name – my name is too hard for you to say. Are you a teacher?'

'Sort of,' I said. 'What about you?'

'You could call me a traveller,' he said. Out the window, Thais wearing hats like inverted baskets were paddling canoes in the streams that ran next to the tracks. The lanterns on their narrow boats lighted the rippling water and clouds of gnats. 'I just travel here and there.'

'Where do you get your money?'

'Here and there. Out of the air; out of the ground.' He spoke playfully, with a laugh in his throat, in a tone of knowing vagueness.

'Out of the ground? So you're a farmer.'

'No! Farmers are silly.'

'Perhaps you don't have any money,' I said.

'Plenty!'

He laughed and turned, and now I noticed that he was holding a pouch under his arm. It was about the size of a squashed shoe box and he held it quite close to his side, almost in concealment.

'Where does your money come from, Mr Pensacola?'