From the first time we lock lips with someone, kissing is tender, passionate, playful, agressive and any number of other things. I loved reading this piece from the fabulous website How Stuff Works (for the geek in you) on the history and physiology of kissing. We spend so much time pondering the mysteries of orgasm or female ejaculation that we forget to concentrate on everything that comes before that - touching, talking and making out. So learn your kissing history and impress the next person that you swap saliva with.