Very simple achievement.
Use the "Cloud" power-up on any special stage in Wales(UK)
This is the last rally event in the single player calendar. To get the cloud power up you must be in front of at least one player. I would actually suggest being 2nd. If not 1st. As the power up is basically white exhaust fumes from the back of the car. Which blind drivers behind you from seeing the road.
Pick ups are random, but stay in front and you should get it at some point. Press the A button to activate. It doesn't need to effect anyone. Just simple use the power-up and the achievement will pop.
A quick way to get it would be online in a private match or ranked match. In a ranked match you will have to be lucky to have your stage picked(Wales). As it is random, But it would get picked eventually.
I got the achievement in an online match by selecting wales. As my event was picked. I started at the front of the grid. Making it easier. I had not reached Wales in the single player at the time of getting the achievement.
So this achievement is available straight away via online matches.
Any questions. Just ask away.