I think that's a look of terror on his face
Gentle - be gentle! Remember he's just little so - DON'T BITE THE BABY. Gentle remember geeentle. Aw, what a good big sister you are to give him kisses wait are you - DON'T BITE THE BABY.
CHOMP
[Repeat ad infinitum until tantrum or binge drinking, whichever comes first.]
