A tip of the tongue

I never quite understood it, but for some reason it always seemed that when people picked me up they'd sooner or later start sticking their tongue out at me. Usually I'd just stare back at them, befuddled. What was the meaning of this rude behavior? Had I done something to offend them? Is it some ritual greeting, like shaking hands? (I still haven't figured THAT one out - helloooo, people - do you have any idea where my hands have been?)

And then, the other day, I'd had enough of all that so I stuck my tongue out right back at them! You know what? It's fun! No wonder people are always doing this! Now whenever someone sticks their tongue out at me, I respond in kind - and we all laugh like the dickens!