OpenGraph descriptions not showing when using Wordpress SEO (Yoast)

Question

I installed WordPress SEO a couple of days ago and have the Open Graph tags ticked, and they are all displaying fine apart from the page description. Should this be appearing, and am I correct in saying it will be automatically taken from the first couple of paragraphs?

Now I understand the reason for not having automatically generated Meta Descriptions, but right now when we post our articles on Google+, only the page title is being pulled through, so the post looks a little blank.

Is there anyway to get the opengraph description tags to work?