This stitch is worked from left to right, along two parallel lines. Try to keep these lines equal distance from the seam line for the neatest look. Come up at the starting point along one baseline. Do a backstitch to half-way from the origin point. (Your needle should be emerging at the center of this straight stitch.) Make a straight stitch in a diagonal direction up to the next baseline and insert the needle. Come up a little to the left of this insertion point, and make another back stitch just like the previous one. Now work down to the original baseline in the same manner.
This stitch looks wonderful when combined with French knots and lazy daisy stitches. Let your imagination go!