Here's the quick tutorial I promised.
Start with two fQ's. Place right sides together and trim so that all edges are flush and match. Press. Sew all the way around with a 1/4'' seam, leaving a small opening on one side for turning.
Turn right side out and press all seams. Close up turning opening by top stitching.
Fold over the 18'' edge by 1/4'', press. Fold over again 1/2'' to form a casing. Press, and then top stitch into place.
Cut a length of ribbon 52'' long (just right for kiddos, but if you want it longer, that's fine too.) Attach a safety pin to one end, and work the length of ribbon through the casing you just made. Remove safety pin and even out ribbon ends.
Sew down the 21'' edge, with patterned sides together. Make sure to keep the ribbon out of the stitching!
Attach the ribbon ends to each open end at the bottom. Sew bottom closed.
Turn right side out and press.