This video discusses a few ways of providing support for the head during suspension. Never change other aspects of a suspension while the head is attached to the ring; undo the head support before coming down or making adjustments.

Here is a link to where you can buy the clever leather headrest. It's not cheap, but it'll last forever, Danny makes quality stuff.

Here is a way to tie the arms behind the head to provide head support. You can also use the hair for head support.