This will hopefully one day be an extension that replicates this.
This extension is available on the Firefox Add-on Store for both desktop and android firefox.
A proof of concept finally exists, using 3y3 it allows you to encode text that when added to the start of a paragraph in a tumblr post allows it to be read as wungle text.
Making the posts flip over, etc., will also happen at some point.
If you have any problems or suggestions please create an issue and if you have any improvements to the code fork this repo and make a pull request to the dev branch.