Floating Social adds a floating social bar in your website which scrolls to stick with users screen and allows them to share your posts or pages or any custom post types. It is fully responsive and can be customized to your needs. You can even put the social bar to any specific post or page and disable it in other pages. It comes with a drag and drops customization feature.
This is the EXACT same plugin as distributed by the developer on WPMU DEV. The developers’ links are provided above.