"The next step involves the most indispensable element of the Russian banya - the venik, a bunch of birch or oak branches used for whipping one another. Banya visitors typically lie down on a bench on their stomachs and a second person beats their bodies with the venik. This is a bizarre thing to experience, but is in fact surprisingly pleasant. Russians firmly believe in the many advantages of receiving a good beating with a venik: from enhancing blood circulation and killing bacteria to inhibiting premature ageing of the skin."

http://east-european-customs-holidays.suite101.com/article.cfm/bliss_of_the_banya