backoftheheadpalm 

Like the more well-known term "facepalm," but much, much more powerful. Implies wanting to smack the other person causing the emotion up the back of the head.

Typically when the other person is being a dick.

Friend: Dude! I just killed you again with the Spartan Laser! What, you're not even trying! Stop giving it to me!

You: *backoftheheadpalm*

backoftheheadpalm by -stalker. December 13, 2009