Achievement can be obtained by sliding 25 meters along the edge of the ramp. Actually this achievement shouldn't really cause any problems, but because the game for some reason decided not to detect my controller, I had to put in a bit of effort to get it. If you have problems getting it, there is one optimal (at least for me) way.

1. Choose a level with a swimming pool
2. Drive to the upper right corner without losing speed
3. Start spinning to gain speed (don't forget to use the space button on uphills and downhills)
4. When you are sure that you have enough speed to slide the desired distance, approach the edge of the ramp and hold Ctrl

It is also important to accelerate to the right so as not to crash into the stairs.