Sentence:  On the first vert, he reared up the side and let the bike take him out. Midair, he made the 180 turn and slipped back in. This time, as he hit the other side, his whole body slipped off the bike, until only his hands held onto the handlebars. The skaters deliberately turned away as the bikers chanted, ‘<WSD>Superman</WSD>! <WSD>Superman</WSD>! <WSD>Superman</WSD>!' 
Meaning of the word marked with <WSD> tags:  A stunt in which the rider releases both hands from the handlebars in mid-air.