Another, less deadly way of achieving this is finding a steep mountain or hill side with a tree placed on or almost at the end of it. Try sliding against that tree and if you continue to hear the sliding sound, just wait until the achievement pops up.
Accidentally came across this right in the heart of Velen, I think I was on a contract mission where you have to find an entrance into a hill. Running around it I came into sliding and ended up on that tree, and as I knew this achievement from the GOG version I played two years ago, I was just waiting that 10 second and - et voila! :-)