Regular bumps allow for multiple turning options. At any time the slier can choose between sliding down the backside, staying in the middle of the trough, or banking on the outside.
Monster, chaotic bumps such as
@mdf perfectly displayed above, require the skier to ride the trough all the way around. Trying to scrub speed earlier will result in a turn directly into the near-vertical part of the bump. There's no option but to give it up to gravity until finally coming to the next fluffy flat spot. As mdf's photos show, almost every bump has a nice spot for a speed-killing hockey stop; you just need the confidence to keep your butterflies in check until you get there.
Keeping a good body position is necessary in nice bumps; in the really tough ones it's absolutely critical that the skier doesn't succumb to those natural - but disasterous - defensive upper body movements that we all know so well...