For two weeks before Sawau tribesmen from the island of Beqa in Fiji perform a firewalking ceremony, they have no contact with women and don't eat coconut. If they mess with "the rules" their feet are liable to get badly burned during the ceremony.
While in Fiji, I watched fire walking, not on Beqa, but the tourist version at the Outrigger on the Lagoon, Fiji on the island of Viti Levu. Now you can watch it too. (Funny thing, when the video begins, someone nexts to me coughs and it seems as though it's from the smoke you see.)
Read about the tradition of fire walking here. The performance sticks close to what is described.
(And remember, "vinaka" means "thank you.")
The population of Fiji is half Indo-Fijian, the descendants of Asian Indians brought to Fiji in the 19th century to work in the sugar cane fields. One guide told us that Indians have a fire walking tradition too, but theirs is religious, whereas the Fijian version is purely ceremonial.