Allow a tag to be automatically "collapsed"
Allow people to create content warning tags that make it so that you have to "click to view" content, unless the person viewing it has that tag whitelisted. The collapsed box should show what was tagged that made the post be collapsed.
Probably it can be anything of the format 'CW thing' where 'CW' invokes the auto-collapse behavior, and 'thing' is the thing being blocked
'CW suicide' is a really good example of this