I you cut lots of strips parallel to the selvage edge there is less need for a stablizer (either a backing of muslin or paper). If you cut your strips the other way they get stretchy easily and need the stablizer for sure. You can gently tug on fabric and determine the direction to cut. Here is a link to explain the terms: selvage, grain, bias. Here they are making bias tape--and want the stretch:
http://www.makeit-loveit.com/2011/01...-bias-and.html