A slug is an area on the pasteboard in an InDesign document in which you can type comments to your printer, coworkers, etc. You can specify slug parameters in the Bleed And Slug pane of the New Document dialog box as you create a new document. The only problem is that the slug area is typically non-printing and trimmed. There is, however, a way to get a slug to print.
To print the slug area:
Depending on your printer and document size, you may also need to select the Scale To Fit option button on the Setup panel in the Print dialog box.Get your non-printing slugs to print (InDesign CS2/CS3/CS4/CS5)