Savina Handmade Horn Sewing Tool - that Purple Thang Style Drawstring&Elastic Threader, Multifunctional Fabric Guide Tool for Quilting Craft Projects

You could use a piece of string to knit around and tie the drawstring to the end and pull it through. A bodkin is a longish flat piece with an eye (like a giant flat sewing needle. You put the drawstring in the eye and use the bodkin to lace it through. Amazon