From the answer to Is a cloth covering required for Tachanun?:
The Aruch Hashulchan (131:7) and Mishnah Berurah (131:3) both say that one should cover his face with a cloth and not merely one's hand, because a person's own flesh can't be considering a covering for itself.
What about hair? Is hair considered an acceptable covering for this, or is it still part of the body? Assuming your own hair, attached to your head.
In case anyone is wondering how this would even work... i need a haircut.