This unofficial TaleSpire plugin adds a button to the dice tray to allow making private rolls to GM. Only the player and the GM will see the dice and the results.
This plugin, like all others, is free but if you want to donate, use: http://198.91.243.185/TalespireDonate/Donate.php
1.0.1: Modified chat messsage to include (Private) identifier instead of player name
1.0.0: Initial release
Use R2ModMan or similar installer to install this plugin.