Here is a tutorial I am offering at this year’s International Quilt Festival Open Studio.
Measure quilt back from edge to edge in the direction where the sleeve will hang. This will be your length. (top) The width will be 9 inches. (bottom)
Place your sleeve right side down. Fold your nine inch edge a ¼ inch in on each side. PRESS. (top) Fold another ¼ of an inch on each side. PRESS. Then machine stitch close to inner edge. (bottom)
Bring the bottom edge up to meet (raw edges) wrong side together. (top) With wrong sides together, sew a ¼ inch seam the length of the sleeve. Begin the seam about ½ inch from the end, backstitch, continue seam to the end, then backstitch. This prevents the tail of the thread from hanging out the end of the sleeve. Press to form a new crease at the folded edge. Baste a large stitch ¼ inch along the new folded edge. (bottom)
Place your hands into the sleeve rotate sleeve to position basted edge on the bottom and the stitched seam on top. (top) Position the two seams over each other. Gently press your top seam open. Press entire sleeve forming two new creased folds. (bottom)
Take sleeve with opened seam side down against quilt backing. Center along quilt back, pin sleeve along pressed edges to the quilt back. The top of the sleeve should be about ½ inch from the top of the quilt.
Hands sew top of sleeve, being careful not to stitch through to the front of the quilt. Then hand sew bottom sleeve again being careful not to stitch through to the front of the quilt.
Hands sew bottom edge of the sleeve sides to the back of the quilt. I recommended that you double stitch or tack the corners.
Remove the basting stitch to give the sleeve the needed “D” shape for proper hanging.