MY DIY | BFF Cross-Stitch Case. You Need: Cross-stitch Case, Needle, Embroidery thread, Sharpie. First, draw the half heart shape on the phone case with your sharpie. Next on to stitching, I started on the top row of the heart with a ///// stitch. Then, crossed back over it to create an XXXX pattern. I worked down row by row, alternating between red and pink thread. Knot in the back to secure.