I had to do this in a class I took. We refolded the fabric end to end and taped two long rulers together. The teacher held onto the rulers and I used the rotary cutter. Gotta tell you - it wasn't the most fun thing I've ever done and I can't believe the teacher held those rulers while I was moving that blade towards her. I think I would have done it the other way. I now have a pattern that has me cutting two 6 1/2" strips the length of fabric and I'm a little nervous.