Maybe some historian here could enlighten me. Thanks.

I suspect they were usually coined by more prudish societies, like the British, etc. I suspect that in some cases it was intended as a subtle insult.

Of course it would be ridiculous to think that the russians invented tit fucking, or that the greeks invented anal sex, or that the french invented oral sex, etc.

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I think that the origins of these terms are derived from stereotypes of certain nationalities. The Greeks didn't invent anal sex, but anal sex between men and boys was fairly commonplace in ancient Greece, particularly in temples; consequently, anal sex is referred to as "going Greek".
The French have a reputation as being amorous libertines, so I surmise that a particularly intimate style of kissing was labelled "French kissing".
I had no idea that Russians had any sexual proclivities.

Condoms:

English -French Letter

French - La capote anglais ( English Hat)

I guess the ancient Roman did the same thing to the Greeks.

http://en.wikipedia.org/wiki/Anal_sex

later Roman age Greek poetry, anal sex became a common topos, represented as taking place with "eligible" youths: those who had attained the proper age but had not yet become adults. Seducing children into the practice was considered very shameful for the adult, and having such relations with a male who was no longer adolescent was considered more shameful for the young male than for the one mounting him. Greek courtesans, or hetaerae, are said to have frequently practiced heterosexual anal intercourse as a means of preventing pregnancy. The acceptability of anal sex thus varied with the time-period and the location, as Ancient Greece spanned a long time and stretched over three continents and two major seas.

For a male citizen to take the passive (or receptive) role in anal intercourse was condemned in Rome as an act of impudicitia (immodesty or unchastity). Free men, however, frequently took the active role with a young slave, known as a catamite or puer delicatus. In fact the Romans thought of anal sex as something specifically "Greek," although Roman men often availed themselves of their own slaves or others in this way.

I just came across another one that I never heard before - Italian.

Under the RB Clueless, it is defined as "penis rubbing between butt cheeks." Any idea how this came about?

Syphilis had been called the "French disease" in Italy, Poland and Germany, and the "Italian disease" in France. In addition, the Dutch called it the "Spanish disease", the Russians called it the "Polish disease", the Turks called it the "Christian disease" or "Frank disease" (frengi) and the Tahitians called it the "British disease".

http://en.wikipedia.org/wiki/Syphilis

Aquí se queda la clara...