Dogs can't eat chocolate because it has something called theobromine that makes them sick.
Cocoa butter is made from the same plant as chocolate, but it has a tiny bit of theobromine, so it's okay if your dog licks a little off their skin.
Cocoa butter is good for dogs' skin and fur. It's often in special doggy balms and conditioners that make their fur shiny and soft.
Make sure you use products made just for dogs because some things in human products can be bad for them.