Using conditional with bookmarking Icons in postbit

Where do I put a conditional in place in order to control when and to whom the social bookmarking icons are displayed with each post?

The icons are shown either never, on the first post only, or on all posts.

Thanks Michael. What I'm actually wanting to do is use a conditional to show the icons only to users who have selected a specific option in their UserCP. I was hoping the code to display the icons is in a plugin/hook that I could easily edit through the plugin manager.