Add Mac OS X Screensaver App to the dock

  1. Go to the Finder.
  2. Select Go from the main menu and then Go to folder....
  3. Enter this path/System/Library/Frameworks/Screensaver.framework/Versions/Current/Resources and click Go.
  4. Locate the ScreenSaverEngine item.
  5. Drag it to the dock to create a direct access link.
  6. Voila. You now have an icon in your dock to immediately start your screensaver and lock the screen.