Fashion loves to change the rules and catch us out. One of my all-time favourite glossy magazine coverlines is What's Sexy Now. I love the brazen nonsense of the notion that Karl Lagerfeld declares he is over clavicles and loving side boob, or whatever, and all over the world our primal impulses are reprogrammed. Clearly, it doesn't work like that. What's sexy now is not that different from what was sexy last autumn. And yet, and yet, we all react to newness. If you don't have anything new to say, people stop listening to you. Clothes work in much the same way: you can't keep banging out the same look day after day and expect it to have any impact.
Fashion has erogenous zones, and they move all the time. One month it will be statement necklines, the next it is all about cinched waists or peplummed hips. This is perhaps the easiest way to ring the changes in your wardrobe. All you do is turn up the volume on one element of your look.
While we're on the subject of erogenous zones, skirts are about sex, apparently. According to Miuccia Prada, who without a doubt owns the fancy-skirt-with-simple-sweater look, waist-up dressing is cerebral and decorative while below the waist is about sex, birth, earthy stuff like that. Who are we to argue with Mrs P? And there's something in it. Wearing sequins on your behind is a different kind of dressing up than wearing a sequined collar on your blouse.
Could this be why the notion of wearing a loud skirt with a simple top seems outré to most people? Because we are so buttoned up and British? It could be, but I suspect it has more to do with the fact that the one piece of fashion wisdom every female seems to absorb at a tender age is that solid, dark colours can be used to make sections of your body slimmer. The fortunes of the black trouser industry are built on this adage.
Leaving aside subconscious prudishness, and enslavement to does-my-bum-look-big-in-this judgment, there is one good reason not to wear a skirt like this, and that is if you are going to a restaurant. Think about it. Pointless. This is a cocktail skirt: standing or bar stool-seated evenings only need apply.
• Jess wears skirt, from £570, by Peter Pilotto. Blouse and shoes, both from a selection, by MaxMara.
Photograph: David Newby for the Guardian. Hair and make-up: Jen Fechter.
