Philematology oder ein Kuss macht kein Loch.

Andy Warhols "the Kiss", 1963

• Anthropologists report that 90 percent of the people in the world kiss. 
• The orbicularis oris is the muscle running around the outside of your mouth that allows for the basic kiss. It changes the shape of your mouth while you talk, and it puckers your lips when you kiss.
• Bonobo apes kiss one another frequently. They kiss to reduce tension after disputes, to reassure one another, to develop social bonds and sometimes for no clear reason at all.
• About two-thirds of people tip their heads to the right while kissing. Scientists believe this preference starts before we're born, when we tip our heads to the right in the womb. 

find out more about kissing here, here or here. 
The facts above are taken from the kiss-quiz you find on the last link (and partially edited)
"Ein Kuss macht kein Loch" ist ein venezianische Sprichwort, sagt Wikiquote