The french kiss is a kiss where the participants' tongues are used to touch the other participant tongue or lips. This is an expression I have heard since I'm little, but I am very curious about the possible origin of this expression. It seems that the expression is British, as there is a lot of expressions there using the word "french", such as French letters, to take the French leave or excuse my French.
Wikipedia seems to describe the etymology this way :
A French kiss is so-called because at the beginning of the 20th century, the French had a reputation for more adventurous and passionate sex practices.
But is that really all ? Is the expression that recent ?