WRC: FIA World Rally Championship

You can perform a slide in various ways from powering into a corner and steering hard, pressing the handbrake to initiate the slide, using the brakes in a similar way to the handbrake or by slowing down and using the acceleration from the car to start a slide.

30meters (99feet) isnt a very long slide for a rally game so this achievement will most likely come in one of your early events.

Here's a video to demonstrate a handbrake slide.