Last week, a neighbour kissed my baby on his lips. I was so surprised, I didn't even respond. I think it's unhygienic and disgusting. Am I overreacting? How can I be polite, but make sure this doesn't happen again?

I'd definitely feel and react the same way! Luckily my neighbours don't do it, but if they will I'll frankly express my disapproval towards the act. But my not so close friends once did. Twas their first time to see my baby then but as frank as I am I told them that I was't happy with the lips kissing on my baby. Straightforward but not so harsh. (used our own language so it's more subtle I guess). And I agree to all the expressed opinions here. We only protect our child and protection could simply mean yourself setting up the rules.