Gay_Communist_Cat said:
If anything it should be "petting head" since that sounds better than "patting head"

Well, "a pat on the head" is a common way of describing the gesture.

Fun facts from TV tropes -- which describes it as an "affectionate gesture to the head" ... In north america, the head bat can be affectionate or patronizing, but in asia, it's often rude because of the spiritual implications of touching another's head. (In Buddhist culture, the head is the highest and most sacred part of the body, while the feet are lowest and considered dirty. So... touching someone's head is REALLY invasive... and it really says some interesting things about asian foot fetishists.

... +1 to either implication. probably depends on if we prefer verbing_noun or noun_verb