Photo data: Jan. 4, 2008, Ken Papai -- DRAGGING the SHUTTER
The terminology means a long shutter exposure with a brief flash of artificial light and "ghosting" will thus occur, as you can see here.

Camera: Canon EOS 40D, 1.3 seconds shutter at f/18 aperture, ISO 100, 16-35 f2.8L lens at 16mm; tripod, and 10 second self-timer so I can run in and pose for the shot.
The 580EX Speedlite flash was pointed at a 45-degree angle; this was shot in Av mode (aperture priority) so the flash is merely used as a fill flash, i.e., to help illuminate the foreground (my face).
Shot Raw and white balance set to 5400K in PS CS3 software. image size here = 880x745, 324 KB