Why am I reminded of John Cleese lampooning sex education in Monty Python 'The clitoris!? Go for the clitoris!? Give her a kiss boy! Thats the way to get the juices flowing! Don't go diving straight for the clitoris!'

The lips are among the most sensitive areas of the body and are also the most sensitive areas that are on display and easily accessible. Well, in most social contexts anyway. After all, we rarely walk around with our nipples and genitals on display... So the social and intimate nature of kisses is understandable - any contact of lips to skin or lips to lips or even the slight pressure of air as someone whispers close to your ear can be incredibly erotic. It also implies a level of trust. After all, who do you kiss? Friends, family, lovers. People you tend to trust more than strangers. Bear in mind, in order to kiss you, you are letting them get close enough to attack you and, yes Icey you are right, allowing them to potentially infect you with viruses and bacteria. Though I have to say that the chances of getting anything infectious is usually moderated by the antiseptic nature of saliva and other protective factors.

Watch dogs, they do the same thing. Though for them 'kissing' is more sniffing - both the face and the behind. To allow another dog to sniff means that you are not overtly hostile to them. Most dogs when they meet for the first time will be wary - they'll watch each other and sniff cautiously. They need to know they can trust the other enough to get close enough to be intimate. Then they get more enthusiastic about it and go for the arse