For a few weeks now, my 11.5 month old is doing this new thing where she bites my arm/shoulder when I am carrying her or if I take something away that I do not want her playing with. I am the only one she does it to. It really hurts and she thinks its funny and keeps doing it, and I have no clue how to discipline a baby her age. I sternly say "no" and shake my head, but she laughs and thinks it is a game! I am not sure what else to do...I do not want her to do this to other people or make this a habit!