Swaffelen

Swaffeling is the way to drive the woman (or if you prefer man, such as some dubious characters) of your dreams to new unprecedented heights and fabulous moments of pleasure. Only men can practice this erotic expression (women also, provided that they are in the possession of sex toys).

The swaffel stands or falls with an important factor. The swaffeller must be in the possession of a so-called top-heavy penis. This means that the penis must not be fully stiffened, though it mustn't be soft either. Top-heavy is a state in which the penis hangs approximately horizontally, and it in which is possible to swing with the penis. Then, take the object to be swaffeled (by preference women's bottom, leg or breast) and slap it gently. Do not hit too hard to prevent bruises and broken bones.

History:
Adam and Eve appear to have done it, the Romans enjoyed it very much on their 40 years lasting journey through the desert, the Jews enjoyed it...
And then in the early middle ages, the noble art of swaffeling was lost. Many feared that the swaffel phenomenon had been taken away forever from mankind, however, on a booze-holiday in Blanes a group of youngsters rediscovered swaffeling, and even perfected it!

source: www.urbandictionary.com