Rated 5 out of 5 stars

by MdG on Jan. 17, 2016 ·

Simple and effective. It would be even better if it would offer the option to always open certain domains in a private tab...

This review is for a previous version of the add-on (0.1.9). 

by Infocatcher (Developer) on Jan. 18, 2016 ·

You can try https://addons.mozilla.org/addon/auto-private/ extension.