how do you protect?
(please note that this only applies to worlds you own)
Go into the Menu thing on the top-right, and click "Make an area owner-only" or "Make an area member-only".
The difference is that owner-only is darker than member-only (and only lets you write in it, obviously) and member-only allows anyone you add in the options to write in it.
Edit: and to undo it, click "Default area protection".
Edit 2: wait you meant in /trogtorcity? i guess that is up for trogtor to decide then