Many so-called swinging couples search – largely in vain – for another female for their mutual pleasure or merely for hers, excluding any male participation. Many others will seek out men but rule out the involvement of other females. And again, many will attend swing-clubs for the view and the companionship, but will actually have sex only with one another. So-called ‘soft-swingers’ engage in oral sex, stroking and kissing with others, but regard penetrative sex as their own exclusive terrain, and advertise themselves as ‘ultimate own partner only’. All these (though I may on occasion dissent), call themselves ‘swingers’.

As for orgies, many swingers do not attend these at all, preferring to chat on the net and the telephone for weeks, months or even years before meeting their chosen playmates, and even then insisting upon lengthy drinks and dinners before they consent to engage in physical intimacy, yet still these call themselves ‘swingers’.

Most of us play freely in, and in front of, crowds, yet some soi disant swingers are so reluctant to perform sexually in front of others, including even their own partners, that they insist on ‘separate room’ sex – a strange ritual far closer to the wife-swapping of yore. And, of course, many ‘vanillas’, as non-swingers are called, have experience of threesomes and exhibitionist sex in larger groups, but do not call themselves. Nor think of themselves as ‘swingers’.

Swinging is broadly divided into private ‘meets’ - usually today organised after a brief exchange on the internet (though Aidan remembers the bad old days where he would write to a PO Box in response to a magazine advert), at which one couple, single man or single woman will visit another and, if the chemistry is there, have sex and, perhaps, make friends - and the party scene, at which the same process is obviously hastened amidst a crowd.