'It would be madness,' Tim Woodward, a practising sado-masochist and publisher of Skin Two, a magazine at the 'soft' end of the S&M market, says. He describes the practice as highly ritualised and requiring trust.
Mr Woodward believes the sexual thrill in S&M comes through 'power exchange'. Through sex, heterosexual and homosexual couples exchange dominant and submissive roles. 'The thing to understand about S&M is that it is a continuum. Most people would be open to spanking or having their wrists tied. Only a tiny percentage go to the length of setting aside rooms in their house.'
Steve works for a company which specialises in strait-jackets, handcuffs and basement-to-dungeon conversions. He believes S&M has a 'power' dimension but is fundamentally about the inflicting and receiving of pain which heightens sexual pleasure.
'S&M is not usually risky. It is a small world and most people are introduced through friends of friends. Going home with a stranger is not what it is about. It is much more of a head-trip than that. The pain can be mind-altering.'
Steve says the numbers practising S&M has not risen; he believes people have a predisposition to S&M. Increased fashionability has made the trappings of the trade, the leather Nazi-style caps, the leather and chain jackets and the body piercing, more visible.
Scientific explanations of sado-masochism are 'highly speculative' according to Dr John Bancroft, author of Human Sexuality and its Problems. While power is an issue it is 'not a sufficient explanation'.
Dr Bancroft says S&M involved certain well-understood scripts. One explanation is that the ritual of S&M made safe what might otherwise be a dangerous exploration of power and submission. By another theory S&M incorporates childhood feelings of guilt and punishment into the sexual act. What little research there is, concludes that S&M is of far greater interest to men than women.
Dr Martin Cole, director of the Institute for Sex Education and Research, believes that sado-masochists are neurologically 'wired' differently. It is a case of nature, not nurture.
No therapy, he says, can change their behaviour. 'All you can do is get people to understand and accept themselves and to do what they do safely.' S&M, he warns, is 'high risk' but that can heighten the sexual experience.
'Normal' couples may think S&M is a million miles from their own experience. But Dr Cole says those shocked by the notion of a heavy spanking session should not forget the more common lovebite. 'It's not a qualitative, just a quantitative, difference.'