Whipped fly stitch is also known as whipped attached fly stitch. Whipped fly stitch produces a branched line with a central ridge.
First work a row of fly stitch.
Whip the row of fly stitch in a second thread.
Be careful not to pick up the ground fabric or split the fly stitches. Use a blunt-ended tapestry needle while you are whipping to avoid doing this.
This stitch has lots of creative possibilities in hand embroidery as the thread that you use to whip with can be of a heavier weight to the foundation stitches or a metallic or fine ribbon of contrasting colour. Experiment with contrasts of texture and weight to create variety.
There are a number of varieties and developments of Fly stitch. These are listed under Closed fly stitch, Plaited fly stitch, Reversed fly stitch, Threaded fly stitch, Threaded reversed fly stitch, Whipped fly stitch, and Whipped reversed fly stitch.