How to post something personal under a read more tag and prevent it from being reblogged

Edited to add: This doesn’t work anymore. (Since asks are now rebloggable)
Someone wrote instructions for this that people seem to be having trouble getting to work. Here’s a restatement that I hope will be more useable. 
  • Send yourself an ask. It doesn’t have to say anything in particular. You might use something indicating the subject.
  • Respond to the ask. In the response box, click the button to enter a read more break (it’s between the bullet list button and the camera)
  • Then it will show up as an answered ask, which can’t be reblogged
  • So jerks can’t easily reblog your painful post to make fun of you, and things are much likely to become unpleasantly viral.
  • (This isn’t effective against really determined trolls, but it helps against some of them)