Whatever turns you on

Pure sex is the come-on, but do London's two current shows of erotica really hit the G-spot? Tom Lubbock is left only partially satisfied

Sex. Sometimes you find notices in pubs that begin like that, and you read on stalk-eyed. "SEX. Now that I have your attention, please bring all glasses in from the garden. The Landlord." And, of course, you feel stupid, realising your helpless knee-jerk excitement at the mere word. But in their own stupid way, these pub-notices make a sobering point: the point being that sex has become for us the very epitome of the interesting and the important. It's such a big thing, we're hard pressed to say why it's interesting or important. It could be anything.

At the Design Museum, there's an exhibition called "The Power of Erotic Design", and it's not blind either to power of certain basic terms. At the entrance there's a video screen that flashes up with almost subliminal rapidity the words: phallic, hole, dominate, curve, instinct, Freud, taboo, seduction, touch, want, dream, perversion, reveal your fetish - a device playing precisely the same trick as the publican's notice, though this time the promise is going to be kept. But what should be in such a show? At this stage of history, it takes a very firm mind to insist that something isn't erotic: you just sound prim or unknowing. And surely most things the Design Museum is concerned with could be said to have some sort of eros. The problem must be what to leave out. Or not, as it turns out. The problem here is scarcity. The show concentrates on 20th-century artefacts, and includes household objects, furniture, vehicles, posters, garments, adverts and fine art works. But there aren't all that many, and the patchy selection only prompts queries, like (if you're going to include Surreal art) why two pieces by Max Ernst and none by Meret Oppenheim? Choices look compelled rather than rigorous. The general message you get is: there's an awful lot of erotic design about, but unfortunately we couldn't get hold of it.

The reason perhaps is the show's bias towards the obviously and deliberately erotic. That's certainly the impression from the overall layout, through designed by Nigel Coates the architect. It's a tacky attempt at the atmospheric: everywhere low lighting punctuated with red neon, swathes of black gauze running round the walls and making detours so as to curtain off several of the actual exhibits. The catalogue speaks enthusiastically about the erotics of space, but tart's boudoir is all the exhibition can manage.

And with the individual pieces, there's very little opportunity for some old buffer to say: now you're not going to tell me that that's sexual! No, old buffers will swiftly be worn into assent, by perfume bottles and furnishings and pictures that wear their private parts on their sleeves. Here is Dali's sofa in the form of Mae West's lips, and Allen Jones's bandage bunny girls doing service as a table and a hat-stand, Hasanori Umeda's Rose Chair, multi-foliate layers of red softnesses with cunt written all over it, and the Eve Machina, a motorbike with a Perspex cover modelled in the shape of a bent-over girl. The phallus puts in a few thinly disguised appearances, too.

It's not all like that. The good erotic object is one that performs its own seduction on the viewer, draws you in with aesthetic curiosity. One of the best things here is Carlo Mollino's Floor Lamp, with its shade made of two great incurving wings of parchment that curl round each other without ever touching, though you keep thinking they must do. Phillipe Starke's Wim Wenders Chair is a lean and literally horny object, which challenges the eye to imagine how you could sit on it without buggering yourself. Isamu Noguch's Radio Nurse (a curvaceous bakelite radio) seems to contain a rude pun you can't quite put your finger on.

Among these things, the adverts (Haagen-Dazs naturally) and the fashion (Vivienne Westwood's Nurse Shoes, super-high heels with snubby toddler toes) look like easy pickings, though Alexander McQueen's black lace dress, armless but completely enclosing the head, does strike an authentically pervy note. And I'm not sure it was a good idea to include any 2D art at all. Beardsley and Hans Bellmer are beautiful dirty draughtsmen, but the omission of the catalogue of modern porn is left looking like gratuitous good taste.

If the show had sought examples of the erotic among contemporaryish art, which it doesn't, it would have had an embarrassment of choices. For example, the work of Cathy de Monchaux. For about 10 years she's been making tricky object collages, combining hard stuffs and soft stuffs, rich in bodily references. An early piece had something that looked rather like a wind instrument cut open to reveal its crimson velvet insides. But recently things have been getting more elaborate, and at the same time tighter.

Quite a few things at the Whitechapel Gallery look like the wildest dreams of Operation Spanner - exquisite and intimate pleasure-pain devices. Sheets of metal, cut into elegant curlicues and nasty-looking prongs are merged with intricately pleated pieces of flesh-like leather. There are lots of suggested moving parts, hard clamps that clutch, sharp catches that might hook into position. There's an excess of fastening, nuts and bolts at every turn, wires and ribbons that bind and thread. The flesh parts swell, strain and burst apart.

What have we got? There's a sense of delicate ornament, for a start, metalwork that looks part Gothic, part Art Nouveau. There's a sense of mechanism too, the inner parts of clocks and music boxes and sometimes something more industrial. And then there's organism, intimations of youths and tongues, penises and foreskins, labia and vaginas, eggs and pods, open wounds and innards, vulnerably exposed.

But the graftings of form and stuff are so cunningly wrought that the effect becomes elusive. Are the organic bits being cruelly clamped, wracked and bound by the hard and sharp bits? Or are they extruded from them, articulating together? The uncertainty is often compounded with a sprinkling of chalk-dust over the whole object which integrates it. It becomes crystallised, half-way between an old brooch or a fossilised crustacean. This is the basic de Monchaux "matter" - something cruel and beautiful, succulent and sensitive, and you can't say where the boundaries are. It's all so excellently done, I'm slightly puzzled why it isn't more piquant.

The smaller pieces are certainly the intenser. De Monchaux sometimes incorporates these basic components into large-scale constructions, involving plates of glass and cut paper and festoons of black ribbons. And there's one full-blown installation at the Whitechapel, a room within the gallery, with various peep holes and doorways, and inside on the floor a long strip of "matter" flanked by large rectangular slabs of lead. Both ways, effects are dissipated rather than dramatised.

For one thing, the eye always seeks out the intricate bits as obviously the most interesting, and they are only revealed on near examination, so you have a choice of peering close and ignoring the whole set-up, or standing back and losing the fascinating detail. And there isn't a good tension here, because de Monchaux's larger structures aren't themselves fascinating. Her insistent symmetry - everything she makes mirror-images itself - which has an organic motive in the small things, just looks like decor on this scale. No doubt the lead slaps and the black ribbons figure a mourning motif of some sort, but other people do mourning better.

And that's rather what I feel about the smaller pieces too, the ones that satisfy close attention. We've been here already. You can marvel at the craftmanship, the manipulation of ingredients, but as for the concept, you can only nod in recognition. Disorienting objects, yes - but this species of disorientation is something we know where we are with. The mechano-organic mix, the invocations of strange beauty and strange cruelty, the little orgies of metamorphosis - these are Surrealist topics and kicks, very finely and expertly done, but done before. Indeed the very expertise seems to betray this, knowing too well in advance the charge to be deliveredn

'The Power of Erotic Design', the Design Museum, London (0171-378 6055) to 12 Oct; Cathy de Monchaux, Whitechapel Gallery, London (0171-522 7878) to 27 July