Overcasting Stitch
This stitch is used for finishing a raw edge to prevent raveling of the fabric. It’s like a serge seam seamfinish done by hand. If the fabric ravels badly, then do the stich one way and come back opposite direction, forming small X shapes at the edge of the fabric.

Secure the thread. Insert the needle through the fabric and pull it out.
Bring the needle around to the back, keeping the thread taut, and insert the needle into the fabric again about 1/8” from previous stitch.
Repeat until you get to the end of the seam line.
Sew in opposite direction if you need to make a stronger stitch.

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