Not only are kids always putting their hands into their own mouths, or touching everything in sight, or scratching all parts of their body, or digging their noses with gusto, for some reason they want to share the joy by asking you to take a whiff of their fingers.
No matter how much you love your child to the moon and back, there is no way you are going to inhale whatever odour there is lingering on those chubby little digits!
Yes, you can do anything for love, but you won't do that.