Very simple achievement
This is in Act 2, during the part where you need to repair the Shadow Puppet Theater. You will be putting on a princess hat, and taking part in the Shadow Puppet Theater. Get through normally until you get to the part where you need to get onto a tree using a windmill. Shortly after that, you get to the crocodiles. Wait at the edge for the first one to shut its jaw, and then start jumping across. You have plenty of time to go across.
If you die, hit the guide button, and then quit out, and re-launch the game, as some users have told me that simply restarting from the last save did not always work for them, and their achievement remained locked.
Use the video below to help with visualization.