When we watch others shed their clothes, what do we reveal about ourselves? The Chippendales are in Britain this month to kick off a 20-city European tour, and the girls at the Spearmint Rhino lap-dancing club are always available. This week, I have been to both to wonder what – if anything – is exposed alongside the flesh?

In Edinburgh, the Chippendale audience piles in. It's a Barry Manilow convention attacked by a hen party and digested by Sex and the City. There are old women, young women, pretty women and angry women. Everyone is in a group – there are no solitary customers – and everyone wants to sit together at the front, close to the nudity. I expect to see women climbing on to the chandelier, like bats crawling up a wall. They are excited – and showing that they are excited. Their behaviour is precisely opposite to what women are supposed to do when they like men.

What are you here for, I ask one group of teenagers. "Naked men!" they scream. What about you, I ask another lady, who must be 80. "Antique furniture is wonderful to see on stage," she quips.

The hall goes dark and a voice shouts out: "Welcome to the ultimate girls' night out in Edinburgh! Don't forget to visit the merchandising stall on your way out! Are you ready?" Yes, we scream, and out come the Chippendales, dressed as builders. They swing their thighs, and look ecstatic, like cartoon heroes.

It feels joyous. I am clapping. I don't know why I am clapping, or when I started. And I don't think we are clapping the Chippendales as they churn through every hackneyed female fantasy – the policeman, the fireman, the soldier, the gangster. We are clapping ourselves, because we can be lecherous and bestial, and we can scream it.

The Chippendales walk out into the audience. I was expecting the bolder women, the ones who leap into the air to catch the Chippendales' T-shirts like expert netball players, to lunge and go for tongue kisses and intimate gropes. But it doesn't happen. When we are offered them at close range, we go shy. Instead of running up to them, we move away. We seem to be avoiding them. There is not a single woman here who actually wants to have sex with a Chippendale. We are all mouth, and no panties. Sex has left the building. We want cuddles, not tongues.

The Chippendales respond by becoming avuncular, and gracious. They hug us and kiss our hands. They have turned from sex gods into kindly male relatives. Outside I meet a woman who jumped for a T-shirt, fighting off other women to get it. "I'm not that bothered about it now," she tells me, "Do you want it?"

It is a fantasy, and the women here know it is. They seem happy, almost relieved, to let it go. It was a day trip to Disneyland where Mickey Mouse has monster abs.

The Spearmint Rhino Club in London, by contrast, is subterranean and windowless. There are a few men sitting alone, watching a naked woman dance. It is a pensive dance, oozing melancholy. Around the room, perhaps 20 young women, in tiny dresses and porn-star shoes, vie for the men's attention. It doesn't feel joyous; if the rhino had a face, it would be weeping.

The financial dynamic is different. The women pay the club £85 a night, but will earn £20 for a lap-dance and £400 for a "sit-down", where they accompany the men to a private booth and dance for up to an hour. To earn the money, they have to beg. They have to walk up to the men and persuade them to pay the cash. They all have different techniques. One smiles from a distance. One bounces down on to a man's lap. One licks her lips.

I watch an elderly man with the face of Count Dracula holding hands with a gloriously beautiful young black woman. He hasn't booked a dance yet but she is holding hands with him in hope. He squeezes her thigh. She laughs. Another man watches a blonde pole-dancing on the bar. He is staring at her, but yawns openly. She smiles, puts her fingers to her lips, and says, "Shush".

The manager brings two girls over to speak to me. One is about 30, with a beautiful cat-like face. The other is younger and has the open, perfect face of a child. Her breasts are totally exposed. Do they ever get aroused dancing? "Never," says the child-like one. "It is like any other job," says the other, "You have your down days and your up days."

"There are four types of men who come here," she says. "There is the one who thinks he will meet his next wife. There is the curious man. There is the businessman who brings his clients to nail a deal. And then there is the man who never spends any money." She gestures towards Count Dracula. "He is here four times a week and never pays for a lap-dance." He is still touching the black girl's thigh.

So why do they do it? "The money," says the younger girl. Sometimes she makes £2,000 a night. What do you enjoy about it? "Nothing," she says. "You imagine hearing the same conversation every night for four years. Shall I ask you what your tattoo means 20 times a night?" And why do the men do it? "To pull a stripper is on every young guy's list," says the older girl. "The older men know we will talk to them. They have their pick. It's a power trip."

I didn't want to come to a conclusion as prosaic as Chippendales good, lap-dancing rhinos bad. Even as I watched the Chippendales play dirty cowboys, I wondered why they were doing it. But at least they were worshipped. The power dynamic at Spearmint Rhino seems entirely different. The men can make these beautiful women compete for them, when in real life they never would. There was no joy or even appreciation. As I leave, I wonder – have I seen a dark part of human sexuality, sliding wonkily down a pole?

This week Tanya watched the Mariinsky Ballet Company perform Swan Lake at the Royal Opera House. "Ballet dancers don't eat. Were their exquisite movements really shouting, "I want some chips!"? She read Vanity Fair. "Michael Jackson is still completely dead".