Jazz musicians often give each other the "head" or "top" cue by patting their hand on top of their head, which is usually meant to make sure everybody "goes back to the head," or starts playing the head again the next time the "top of the form" comes around. On the unfortunate occasion this may be due to confusion about "where" the top of the form actually is if the musicians get off-sync with one another, or a frantic attempt to regain composure and finish the performance, as playing the head to end a piece is default jam session protocol.