If you like to sew on stretch knits, a twin needle might just become your second-best friend. (Your machine itself is your best friend, right?) A twin needle will sew two parallel lines of stitches on the top of a piece of fabric, and a single zig-zag stitch underneath. This makes a decorative stitch that is also stretchy.
[photo from Kadiddlehopper]
[tags]sewing, tutorial, twin needle, stretch, seam, knit[/tags]