Jaws

My son has found a new way to deal with his frustrations and unfortunately that has manifested itself in him acting like he's a shark and attacking his poor sister and biting the crap out of her arms, legs, toes, essentially anything he can sink his teeth into.

It is always after she has been teasing or picking on him, so it is not like it is completely out of the blue. However, regardless of the situation I'd rather not encourage or at all give him the impression that trying to rip his sister's flesh off is okay.

In the past couple of days he has bit her three times. Once on her toe and twice on her arm. These pictures don't really do it justice. One of the bites was so hard that I literally had to pry his jaw open to pull him off her. He would not let go and as a result he broke skin and left a pretty nasty bruise.

So, any suggestions on how to curb and hopefully eliminate the biting? I'm thinking about getting a punching bag for him to let out some of this aggression.