For this achievement all you need to do is head butt the golden wheel found down the cave. The cave can be found by following the map towards old goat mountain but when you get to the beach instead of turning right go left. Follow the path round till you get to the big cave where you turn right to go deeper into it. Eventually you will find a golden wheel that if you head butt your achievement will unlock.
If you would like a guide of how to find the cave or a video guide for the whole achievement I have included my video guide below.