Protected methods is something that is very rarely used, so I have skipped this for now.
Lets say you have two obects in instantiated from the same class:
Let's also say you have a protected method called "prot_method".
In order to apply this method on objectB, then you can do it indirectly via applying a method to objectA, and passing objectB as a parameter into that object.
See "excerpt section of this post"