Social bookmarking…

Hi everyone!

Just a general question.
I found an awesome social bookmark plugin that I want to use.
My site hasn’t gone live yet.
However, it’s generated online, and we are supposed to add the code to the posts, I guess to every post individually.

It’s at: https://www.sociofluid.com

Is there a “centralized” plugin that will add specific bits of code to each and everyone of my posts??
I just want to “add” it ONCE and then forget about it.
Should I even alter the theme itself?

I searched the forum, but didn’t find anything on this…

Thanx!