Snaking is a method used to increase your speed to level greater than what can be achieved using multiple boosts. Some consider it cheating, but it's awfully difficult to implement it in a useful situation, say, grand prix, or story mode.

Various machines are capable of snaking - Black Bull is a perfect example, although you can snake with other crafts.

Selecting a course with a wide straightaway is normally the best bet to learn snaking. Good examples are Casino Palace: Split Oval, Port Town: Aero Dive, and Casino Palace: Double Branches.

Select a Machine, and set your acceleration to Maximum. While driving on a straightaway, alternate between pressing [L and Left on the control stick] and [R and Right on the control stick] while holding A. Simply sway the vehicle back and forth, and you'll accelerate to speeds MUCH higher than can be accomplished with a few simple boosts. It's hard to keep it up for long (your fingers get awfully sore), but it's great for quick boosts in speed when you can control it.

Snaking is apparently an intended inclusion in the game, and not just a trick exploiting the control system.