Snaking is a technique for experienced players that allows the user to continuously drift back and forth to perform Mini-Turbos on a straightaway. It was first developed as a byproduct of online competition in Mario Kart DS, though the technique has been usable since Mario Kart 64 and was similarly prolific in Mario Kart: Double Dash!! world records.
The technique is essentially a chain of Mini-Turbos. Snaking is easily done by lighter Karts with extreme acceleration and handling, low drift and powerful mini-turbos, mainly the Egg 1, Dry Bomber, and Poltergust 4000. An outlier to this rule is the ROB-BLS, which, while heavy, has a fairly good handling stat coupled with a high speed, and is very popular for snaking as well. It is most easily done on wide, linear courses without obstacles, such as Figure-8 Circuit or Peach Circuit, while it makes less of an impact on narrow courses such as Rainbow Road. It is generally looked down upon to use the technique against unskilled or non-snaking opponents in online matches, but it is commonly used in Time Trials to achieve impressive records.
Nintendo has made efforts to remove snaking in subsequent Mario Kart titles. Aside from the massive skill gap it created between skilled and weaker players, which many viewed as unfair, continuing to carry snaking into future games would have made it difficult to balance vehicles. It's likely that most of the above karts' positive traits were supposed to be balanced by their low drift; however, with snaking abusing low drift to go faster on straightaways, they no longer have any disadvantages, and are simply better than the majority of karts in the game. Mini-turbos could now only spark when a vehicle had drifted long or sharp enough, which made attempts to create mini-turbos on narrow straightaways very difficult. While there have been attempts to replicate snaking, all such attempts are not practical for racing, rarely ever making a difference in time or speed and often actually slowing the user down for attempting it.