I saw on QI, or somewhere, I forget where, that apparently the kiss in marriages is based on when the couple would actually consummate the marriage in front of their entire village.
Which is very un-English.
Here in dear old blighty we are quite staid about public displays of sexuality. If, should you happen upon our shores, you should witness this, you can rest assured that these are the acts of immigrants, liberals, vegetarians, bankrupt celebs and the morally destitute.
We have established a parallel class system by which people are able to engage in recreational copulation.
Lower or Working Class: Acts of copulation should be mostly joyless with no exclamations of pleasure beyond some light grunting. Please restrict yourself to missionary position unless it's a public holiday. No toys or other diversions. Foreplay is unnecessary. Please avoid any post-coital conversation or eye contact.
Middle Class: Modest amounts of joy are allowed but try not to upset the neighbours, you still live in a semi and don't you forget it. Some variation in positions is permitted but nothing that may be described as athletic. Try not to dwell on the missionary positions, this is supposed to be fun, not a class protest. Toys of a moderate value are accepted as long as they look kind of normal. Other diversions permitted as long as they seem like a bit of benign cliche. At the end of the act, remember to express your middle-class guilt by asking if it was alright for the other party.
Upper Class: OK, so you own the country and there's not much we can do to stop you. However, interfering with anyone beneath you or dying in the act really isn't going garner you the respect you think your money and influence deserves. A couple of times a year, one of you is going to be sacrificed to the tabloids to give the proles and brown-nosers a sense that you aren't any better than them. Try to make sure it isn't one of the really wierd ones otherwise it'll be pitchforks and burning torches all round.
Technically there is a Royal Class of copulation. You aren't cleared to know about it and the instruction manual is very long and complicated. Best not to talk about it.