I have a Sony DCR-DVD92 and I have done that before. What you do is you accidentally press the record button(haha) then stop the recording. Before you press the record button again, you press the replay button on the bottom of the LCD screen. It starts replaying the LAST scene. There is a little trash can button on the LCD, you press that and it will work.

Note: Does not work with DVD-Rs!!!!!!!! Only DVD+-RW!!