Helmeting sounds like a pure urban legend to me. I don't think it's anatomically possible, even though so many people seem to go around acting if they had their own heads up their asses.
Man...there has got to be some anatomical anamoly that can alloy people to stick heads up their butt. I wouldnt want to be on the recieveing end...cuz I think it would hurt no matter what. But if it was your head, you could wear a shower cap or sumthin....lol