"No, it's not working," declares Christina "Tin" Odescalchi suddenly, shaking her head and gripping her paintbrush. "The light's not right. Let's try another position. Can you move around on the bed a bit?" Easier said than done, without flashing your privates around, but at this point I'd flick-flack round the room if I meant I could present Tin with an attractive rear view.
The bottom she finally commits to canvas several hours later is no Elle Macpherson (well you can't work miracles) but I do become the proud owner of my very own nude oil painting. Which makes me a la mode indeed, since privately commissioned nude portraiture has, almost overnight, floated back into fashion as the way to immortalise a moment.
This is something of a turnaround, to say the least. As the poor relation to photography and the punchbag of feminism for years, the female nude portrait has languished as the apotheosis of modern naff - the sort of thing you'd expect David Hasselhoff or Rachel Hunter to have proudly hung in their living rooms five years ago. Now, with the female nude being seen as less of a political issue - the realisation that it needn't be exploitative and belittling - and with art becoming less elitist and more affordable (anything from pounds 500 to pounds 15,000, depending on the artist), commissioning your own portrait is no longer the preserve of the rich, famous and tasteless.
"Women are becoming more self-assured," says Katy Letman, commissions consultant at London's Mall Gallery, which handles sales for the Royal Society of Portrait Painters, "and the traditional barriers of the nude have been broken down. I think women are particularly attracted to the idea of celebrating their bodies on canvas." That's certainly the case for Miranda Twiss, 37, who has posed for no less than seven portraits (she owns just one of them) for celebrated portrait painter Andre Durand. "I just wanted to have myself painted so that when I'm a wizened old hag, I can walk into somebody's house and see a picture of myself, beautiful, on their wall and remember how I was," she laughs.
Three of Twiss's portraits are depictions of her as Venus, which allows for an imaginative rendering of her proudly Rubenesque body. That's the beauty of the portrait versus the photograph. While the camera never lies (or rather pretends it doesn't) and so can feel voyeuristic and potentially exploitative, with paintings you can at least live in hope of a few kind brushstrokes. "Nude photography always has a sexual edge to it," admits photographer and Dazed & Confused's art director Rankin, who is setting up a nudes exhibition of his work in London later this year. "It's always tinged with the idea of soft porn. That's not how I see it personally. It's the baggage people bring to the image."
Which isn't to say that nude portraits can't be provocative, too. Britpack artist Jenny Saville is well-known for taking her self-portraits to deliberately confrontational extremes; while Jerry Hall no doubt wishes that Lucien Freud, never known for looking on the pretty side of life, could have made a more traditional job of his portrait of her heavily pregnant body. Others, like Andre Durand, enjoy a more erotic and allegorical take on the nude - both male and female. "People are finally realising that the nude is the most beautiful thing on Planet Earth," says Durand, whose previous clients include the Pope and the Dalai Lama (needless to say, fully clothed) and the Olympic diver Greg Louganis (starkers). "People associate the nude with sex. It's very immature and silly. It should never be a sexual experience - sensual and loving yes, but not sexual. We've come out of the period when being painted nude was all about the exploitation of the female, and all this crap. I think that finally all that uptightness is going."
Certainly Durand's clients have no foibles about getting in the mood. Explicit poses are usually the order of the day. "Besides," he shrugs, "I wouldn't work with anyone who is self-conscious about nudity anyway. If people are not sure about having their portrait done, it would stultify the inspiration."
Durand wouldn't have appreciated my coy shufflings around the four-poster, then, as I wheel myself around to Tin's instructions until nothing but my back is showing (fair enough, too - you try working in an office when everyone's examined your nipples over their Sunday breakfast). As I hit my Maximum Modesty pose, Tin - who, to her credit, had been very patient with me - starts cooing, "Ooh yes, your back looks great there, your skin looks fantastic, beautiful lines." Aah, yes, yes, my beautiful lines! It feels remarkably liberating to be a form rather than a person, a composite of shadows, shapes and feminine curves rather than a slightly lumpy journalist with that perplexing midriff.
And as soon as this pose has been accepted, my embarrassment evaporates. We're in it together, our complicity established, so that, by the time I stand up to stretch (which is frequent - it's hard-going leaning on one hand for four hours) and come round knickerless to look at the work in progress, I feel as comfortable with my body as the Whore of Babylon, while Tin, having peered at my bum all morning, doesn't blink an eye.
Whether I would be quite so blase if a particularly raffish male artist was painting me is something I'm not sure about. I think perhaps not. But then, part of the process of having your nude portrait done is actually choosing an artist who you feel comfortable with. I trust Tin because her style was collaborative and relaxed and I feel in control; then again, no one reputable is going to force you to put it about like Moll Flanders if you don't want to (not if they want paying anyway). Take Marco Pierre White, who is rumoured to have commissioned a portrait of himself - sitting naked on a white horse, believe it or not - for artist Jonathan Yeo. White is hardly one to relinquish the reins of power, and unless Marco's going side-saddle, one would suspect that he expects his modesty to stay largely intact.
In other words, the sitter calls the shots. Katy Letman agrees. "An enquiry can take a lot of time, which is good, because it means the clients put in a lot of thought into their selection," she says. "We've noticed a marked request for nude portraits recently, and I have put the clients in touch with the artists, but there's no hurry for them to make a decision. The longer they take, the better chance of them feeling comfortable and happy with the end result."
As someone whose bottom now graces her own living room, I say amen to that.
The National Portraiture Association: 0171 602 0892. Royal Society of Portrait Painters: 0171 930 6844.
Tin Odescalchi: 07050 109533.