I really need this to be a feature, sometimes theres that cause for that event that you are in to, then we should /facepalm
I mean, how hard could it be? Just modelling the hand and head,
Basically what i mean is like this:

What the pictured provided, from a game, is that the guy whos /fp ing (thats the ingame command) is hands first go up, put a slap sound when reached to the head, and after that, nod no.
Yeah, should be a feature...