I just bought this machine. I have played with the stitches a little. Because of the side movement I was thinking when I get ready to add these stitches to a project I would add painters tape or something to show me the 'lane' I want the stitch to stay in. You can't really hold the fabric too much because you don't want to be fighting it or stressing the machine/fabric as it is pulling.
I love the idea of just drawing the lines on the fabric with chalk or something. I will try that!