Heart Photo With Light Saber

I used a Canon Rebel XSi and my husband drew a heart with his light saber in a dark room when I told him to start and I hit the capture button. The shutter stayed open until he turned the saber sideways. The green saber is brighter so he didn't have to turn it. We also did a butterfly. This took several tries to get right but was was tons of fun and a bit romantic for our 5th anniversary!