In case you wondered, paraphilias have nothing to do with paragliding. At least not usually. And no, paraphilias are not potplants. Not ever.
Take a look at our gallery of alternative sex practices.
There are many confusions about this group of sexual desires and behaviours, which some might consider to be the standard deviations.
They have been called perversions or lifestyles, mainly according to whether the person describing them finds them disgusting, or potentially amusing, or is an active practitioner of the one being referred to.
Mrs Patrick Campbell, a great actress and pal of George Bernard Shaw, once commented, when asked about some notorious sexual scandal of her day: "It doesn't matter what you do, so long as you don't do it in the streets and frighten the horses."
I was surprised at the extent to which people misunderstand the reality of a fetish. It is not, as they are called, "a fondness for the unusual".
A vast empire of the unusual has not yet attracted the sexual ardour of anyone, and some of what may drive some individuals into a froth of excitement is very far from unusual.
But there are those who become so very attached erotically to whatever is their fetish, that they are no longer able to have or enjoy ordinary sexual relations without the presence of whatever it is.
It isn't a question of finding it pleasant if your partner wears some leather, or feathers, or attractive underwear, but of not being able to get truly aroused or to relate to them sexually, unless the leather, feathers or underwear are very noticeably present.
It's more than a preference
A man may be more turned on by redheads than blondes - that's a preference. If he is incapable of sex except with a red-head, that's probably a fetish. It is a more-or-less exclusive passion for part of a person or for objects not usually associated with sex.
Thus a foot fetishist experiences profound arousal on seeing feet, and might not be interested in viewing a naked woman or man, unless their feet were visible.
The "looser definition" suggested in the media is definitely not generally accepted by intelligent people. "Any particular body part or outside object that has some pleasurable sexual importance to the person and can create a sense of arousal, but the item is not necessarily a prerequisite for arousal".
This would be a nonsensical definition, according to which every human being ever born would be a fetishist.
It would be a very rare individual indeed, for instance, who did not find some of the primary or secondary sexual organs of their preferred partner to be of "some pleasurable sexual importance". Thus they would all be classified as fetishist by this definition.
When you needlessly and senselessly dilute a definition until it includes everyone or nearly everyone, it no longer has any useful meaning whatever.
For instance there may be some point in considering political points of view as right-wing or left-wing, but if your definition of either "wing" becomes so vast and all-encompassing as to include almost any opinion anyone might ever hold, the classification immediately becomes useless.
Not "really about fantasy"
Yes, of course, a fetishist fantasies about whatever turns them on - so does everyone else. So there's nothing remotely relevant about fantasy in defining a fetish. And, as I said earlier, it is distinctly not "a fondness for less than conventional practices".
That might be an eccentricity, but not a fetish. And nobody with any recognisable fetish is in any way fond of the idea that anything about it is "less than conventional".
Indeed, they are often deeply troubled by this specific aspect of their preference, because it separates them from other people in a sense, and makes them expect to be laughed at or ridiculed by others, if their practices were to be discovered.
People with fetishes often find them highly inconvenient and embarrassing, and severely limiting their ability to simply enjoy ordinary sex with their available partner.
And of course some fetishes are criminal and/or harmful. For instance the Frotteur, who gets his kicks from rubbing his aroused self against someone else in the street. Because this generally involves not only public behaviour but forcing himself upon someone unwilling to participate, it is potentially criminal and distasteful to others.
Similarly, the Exhibitionist, who is pleased by exposing his or her naked and perhaps aroused self to others, and who seems mostly to enjoy the degree of surprise, shock or horror shown by the person at which they aim themselves - they get no fun out of finding a happy and pleased observer, so this too is criminal and intrusive.
People often irresponsibly dilute the concept still further, by needlessly reassuring that enjoying a particular perfume on your partner isn't perverted.
But take, for instance, one of those who posted an anxious question on my forum a couple of years back. This man, married and with children, admitted that he had a very specific fetish. He was very highly aroused by the sensation of rubbing his genitals against the still-warm and wet nappies of infants.
He was insistent that he was not a paedophile, and was in no way aroused by the thoughts of babies themselves or any possible form of sexual contact with infants - it was solely the warm wetness of a freshly soiled nappy that aroused him, to the extent that he had experienced several near-misses at being caught, when engineering elaborate pretexts for persuading mothers to allow him to dispose of their child's dirty nappy. Now that was a fetish.
Could be a real problem
Yes, a fetish is a significant problem where it involves something that could be illegal, which involves acts which are not consensual (lacking the consent of the other person), or harmful to themselves or others. And even if it avoids that particular hurdle, it can make your desires so specialised that it could be hard to find partners.
The internet has been an enormous boon to fetishists, as it has made it far easier to locate others with similar interests, and even if they don't actually meet, it enables them to feel less isolated, knowing that there are others out there who share their desires.
If your fantasy is to spank a very short red-headed and bearded woman, it may be hard to find someone matching this description and happy to be a willing participant, within your own home town. But within the enormous global village of the Web, you may well find a kindred spirit.
I am concerned, too, that the media takes BDSM (bondage and sado-masochism) very lightly, more as if it were a fashion trend, and "just one of those things". Yet there is a disturbing growth within public crime, of sadistic killing and maiming just for its own sake, in the course of other crimes or attempts at crimes.
We live now in a society in which there is a substantial risk that a criminal will kill or cripple you in the course of stealing your cell-phone, even though there is not the remotest benefit to him or the success of his crime, in doing so.
There has to be a level at which such criminals deeply enjoy inflicting pain and terror on others. And this has not always been so, and should not be airily dismissed as "just one of those things". That's a Cole Porter song, not an explanation.
Some fetishistic acts may relate to earlier childhood traumas or highly charged experiences, but their re-enactment within a fetishistic sex act does not provide an effective catharsis and the relief that might be felt is only very temporary, or there would be no need to repeat the act. Where such factors are obvious, highly skilled psychotherapy may help.
And remember that fetishes are not usually about objects or acts that the rest of us would be likely to find even remotely arousing or attractive. These are private passions.
Visiting sex shops
I recall when visiting Denmark in the early years of its escape from censorship, when access to a wide range of sexual materials became considered part of the tourist route, my hosts took me to visit one of the first famed sex shops.
What struck me was the range of topics for which there was apparently a market, things you might never have thought of.
There was a thriving range of porno magazines and films featuring dwarfs, for instance, and not only visual material, but racks full of tight-fitting rubber garments, proudly labelled "Gummi", accompanied by illustrations of the apparent pleasures of getting wrapped into these outfits.
I found them neither arousing nor disgusting, but imagining how uncomfortable and sweaty they'd be, I was simply surprised that anyone could find the idea so attractive.
Professor MA Simpson is Health24's CyberShrink. A South African psychiatrist, he qualified in medicine and in psychiatry in Britain. He has been a senior academic, researcher, and Professor in several countries. Read more of his columns.