t's full steam ahead for sex in Russia.

It's full steam ahead for sex in Russia, where steamy trades fuel the economy.

The first advertisement that greets visitors at Moscow's dowdy Sheremetyevo Airport screams: ''Nightflight: Do it tonight.'' Nightflight is one of the most popular of the many sex clubs that have appeared in the centre of the old Russian capital since Mikhail Gorbachev finally lost control of Lenin's nightmare. The bar is like a high school prom gone crazy.

There are so many women teetering around on impossibly high heels at the Swedish-managed nightclub that there seem to be enough of them to adorn the extremities of every man in the place.

Women outnumber men by at least 10 to one. All are hookers. Most are drop-dead gorgeous.

The ladies of the night swarm in the hundreds there, staring back luridly at any man who so much as glances at them.

There is such a concentration of beautiful women at Nightflight that, sincerely, it may not be equalled anywhere else on the planet.

It is an exaggeration, to be sure, but sometimes at night near Red Square you'd swear the only successful business being conducted in all the Russias is sex for money. Even at 3 a.m. on a blustery winter morning, clusters of 10 and 15 women not considered quite attractive enough or lacking the right connections to work in a nightclub congregate in gaudy outfits at every corner along Moscow's toniest shopping street, Tverskaya, or near the Bolshoi Theatre, National and Metropole hotels and the KGB headquarters to offer themselves for sex.

These are crazy times in Babylon. While babushkas beg for bread and millions of soldiers, miners and government workers go unpaid for months, some parts of the Russian economy are terribly over-heated. This is especially true of the sexual economy. The most expensive sexual emporium in Moscow is reputed to be Up and Down. It can cost as much as $670 to get in the door. The highest cover charge for gamblers is at Karusel, which charges $560 for entry on busy nights.

Across the street from the Kremlin at the Rossiya Hotel, Manhattan Express, which is more bordello than bar, offers a live sex show in a special VIP room for $200 per person or, more accurately, per man, as female patrons are not allowed.

It's only $67 to go through the metal detectors at Dolls, which proudly describes itself as an American-style striptease establishment, but costs much, much more. If the naked nymphs at Dolls don't bend your mind with their acrobatic dances, the prices listed on the menu will. A glass of orange juice is $13, a caesar salad is $21.25, the Dom Perignon goes for $670 a bottle and a gift-wrapped bottle of Hennessy Richard cognac is $5,300. Clients seeking privacy at Dolls can reserve a private booth with bulletproof tinted glass for $1,300. Explaining these absurdities, the manager, Mascha, says, "If we had free entrance all kinds of riff-raff would be in this joint. Look around you. It's peaceful. There is no rudeness. There probably are people in Moscow who don't like girls taking their clothes off, but they don't come in here."

The wild prices and practices of places such as Up and Down and Dolls scare away most Westerners, but there apparently is no shortage of custom from flatheads, as Russia's brush-cut hoodlums like to style themselves. All this makes Nightflight seem like a bargain. The cover charge at the club, which looks no different than a bar in any decent Western hotel, is about $35. That gets customers one soft drink or one gin and tonic. A thimble of Bailey's costs $12.

As for the women at Nightflight, the word around town is that they require as much as $1,000 a night. A Dutch regular says this simply isn't true. The supply so outstrips demand that the businessman, who seems inebriated, boasts that he can take home anyone he wants for $100, $150 tops. Smiling through the smoky haze, the Dutchman mumbles, ''I've come to the loveliest city in the world,'' before taking up with a dusky woman from the Trans-Caucusus with stunningly high cheekbones and a 101 Dalmatians dress wrapped tightly around her taut, hour-glass figure.

Sex may be the post-Soviet Russia's most successful export. Russian women by the jumbo jet-full work as "entertainers" in Japan, Cyprus and Israel. There are so many Russian and Ukrainian prostitutes in Turkey that all young Slavic women there are called Natashas.

The grim reality is that there is very little else that many young Russian women feel they can do to earn a living, so they become prostitutes and strippers. Virtually every well-paying job advertised by Russian companies in any of the local newspapers is for males. Women are sought as secretaries, bookkeepers, sales clerks, waitresses and teachers. Even legitimate jobs for young Russian women are not without their perils. Many Russian bosses consider it part of the job description for young female employees to sleep with them or with clients. Not much is done to hide this crude practice. The code word for it in advertisements and in job interviews is ''biz complexov,'' without complexes.

Small wonder most young women are keen to work for foreign companies.

The dollars or marks are welcome, but the fact that sex is not part of the equation is generally considered to be the most attractive feature. Except that she's perhaps 30 and therefore much older than most of the other women at Nightflight, Tanya's story is typical. The diminutive, chain-smoking blonde can't live on the $80 a month she makes selling cosmetics. For the past two years she has been coming a couple of nights every week to Nightflight to try and snare men with money to burn.

By day, Katya, a leggy, jet-black haired 21-year-old teaches math to fifth graders at School 228 near Metro Novozavodskaya for $100 a month. By night she takes her clothes off for free on stage at Dolls. If a man likes what he sees he may pay her $130 for a table dance. After explaining in a squeaky, child-like voice that she is now teaching her students the theory of volume and space of liquids, Katya says, ''I like teaching very much, but practically speaking, there is no money in it. ''I've had many foreign boyfriends, but frankly Russian men are more generous. ''I love Russia and I hope it will get better. In 10 years time I want to still be teaching.