Responsive Facebook Comments is available in 2 different versions. A Content Plugin and a System Plugin. The Content Plugin can appear automatically at the bottom of the Joomla Article when enabled and the System Plugin has a syntax that can be added any where inside any module or component so that the facebook comment box can appear at the particular place where the syntax is defined.
Please resize the browser to check the responsiveness of the comment box. The comment box automatically resizes according to the browser size and devices used. You can mention 100%(to make it responsive) or pixels according to your requirements.
THE DEMO GOES HERE