Um, sorry to kill the humor, but what is on the sign (and the image in this comment) is actually the superman pose, used to reduce drag in bicycle races, so the town the sign is in may experience a constant stream of bikers in the Superman pose.
if this is a downhill slope, there are people that assume that position when letting gravity push them. it goes really fast but if you hit something, your chin is going to meet the third rib down and both are cracking up but not laughing.
Wait... That is a style of Malaysia's some bicycle... The bicycle name is "Basikal Lajak" (Jumping bike) and it was ment for racing. They usually do that to impress someone. And if you think they f**k their bike its yes but actually no because the sofa is soft and im not gonna explain it.