Military slang that describes someone in the act of walking away after being booted from a tough course like Airborne or Ranger School. The person is humiliated and drags his duffle bag full of kit along the ground behind him. A sobering sight to those still in the course.
Ranger instructor: "half of you won't pass the PT test this morning and will be doing the duffle bag drag before chow."
von Tom.com 3. Dezember 2010