if i had to hazard a guess here, i would say that there is some sort of pit underneath that blanket a la jiffy lube style.
There are 17 pretty amazing photos here. http://www.kulfoto.com/interesting/764/17-most-perfectly-timed-photos-ever/11133/picture My top 3.
btw, I once wore a ziploc filled with vodka down my pants into a bar in college. Are you still in college, lmeister?