NOTICE: If you do not unlock this achievement simutaniously on all 3 versions you will lose the opportunity of obtaining it on any other version (along with the game completion).
You can grab this immediately in Tutorial mode as soon as eating skulls is introduced in the 3rd area of the tutorial (so you cannot eat any skulls until they actually tell you how to do so).
When you get to your 3rd skull save the game on the cloud and load up the other 2 platforms. Then eat the 3rd skull as fast as you are able on all 3 platforms. This achievement is saved when all 3 achievements pop. IF it does not unlock on any of the platforms quickly back out of the platform it didn't unlock on and re-load the save (before doing anything else on any of the platforms!) do it again and it should pop, this is what happened to me and I was still able to get the 3rd to pop!