Plot 'n' bash is a style of navigational information used on road rallies, where competitors are handed the route information at the start of each competitive section, just as the clock is started. The route information must be decoded and plotted quickly and accurately as part of the time taken to complete that section.
Novice crews will often decode and plot while stationary, then drive the plotted route - this is the more literal meaning of "plot 'n' bash". However, as experience is gained, most crews will decode, plot and drive the route simultaneously. This requires considerable skill on the part of the navigator, who must decipher the route and plot it while giving the driver up-to-the-second information about where they are right now, and what is ahead, as well as calculating due times and handling the paperwork, etc. The driver, by contrast, merely drives. This second approach is usually the more competitive, but prone to much larger errors if the navigator misreads the directions.