h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

Some info published in the Daily Mail on Feb 13th (ie in time for Valentines Day (Looks like it was extracted from a book called 'Love and Romance: Facts, Flowers and Fun' by Eve Devereux:

French kissing appears to have nothing to do with France. The French name for such smooches is 'rouler une pelle', which translates, rather unromantically as 'to roll a shovel'.

Kissing is good for the teeth and gums as it stimulates saliva flow, thereby reducing plaque levels.

Like many forms of exercise, kissing stimulates the production in the brain of the neurotransmitters dopamine, norepinephrine and phenylethylamine. These chemicals work in a similar way to emphetamines and create a feeling of exhilaration.

The word 'flirt' comes from the Old French 'conter fleurette', which means to try to seduce by strewing flower petals in front of the object of one's affections.

The stag party dates back to ancient Sparta, when a soldier would hold a party on the eve of his wedding to indicate that his new loyalty to his spouse would not wipe out his allegiance to his comrades-in-arms.

One popular theory about the origins of the word 'honeymoon' concerns the ancient custom in parts of Europe whereby a newly-wed couple would drink metheglin, a kind of mead (honeywine) during the lunar month after the marriage.
An alternative theory is that it is a corruption of the Norse word meaning 'hiding month'. It was common practice for a man to abduct his chosen bride from a neighbouring village and hide away with her until her family had calmed down enough to accept him.