facepalm

To bring the palm of one’s hand to one’s face as an expression of mixed humor and disbelief, disgust or shame; for example, when one is caught off-guard with a particularly bad pun.

To bring one’s face down to one’s cupped hand or hands.

A gesture of bringing one or both palms to the face, with various interpretations including exasperation, chagrin, frustration, embarrassment (one's own or vicarious), etc.