This reminds me of the practice in Egypt where men would intentionally press their heads into the ground when praying in order to develop a callous, colloquially called a zebiba, showing off their piety. Is this still fashionable? When I traveled rural Egypt in 2008 it was omnipresent; one shopkeeper told me he no longer believed in religion, but he had to develop a zebiba nevertheless, otherwise no one would buy from his shop.

Interesting. TIL

http://news.bbc.co.uk/2/hi/middle_east/7469221.stm