This is a great idea I thought of if I do say so myself. I love tying ribbon around boxes of cards I give as gifts but what to do if you want to replace the ribbon after opening the box? The ribbon is untied and what are the chances of tying it in exactly the same place so the wrinkles don't show? And while you and I might be able to tie the perfect bow, since you are giving a gift, will they be able to retie it? And who wants to tie and retie a bow every time you open a box anyway? So I came up with the idea of attaching cord to the ribbon at the back of the box so it can easily slide on and off, the bow staying tied! (Post for the box pictured to follow)
Step 1: Tie the perfect bow on your item. Trim the tails, do anything else you want like add other embellishments to the bow etc.
Step 2: Cut the ribbon at the back, yep, cut it right in half. Being exact isn't important. If your ribbon is polyester or nylon (most is unless it is real silk or cotton like twill tape) you might want to heat set it with your heat gun so it can't ravel. Normally ribbon like this doesn't ravel too badly because it is usually cut at an angle but this time it is cut straight across.
Step 3: Apply a thin bead of glue to the edge of the ribbon. Fold the ribbon over. VERY IMPORTANT do not allow the glue to fill the space, you need a loop for the cord to go through. see photo. Use small binder clips to keep the ribbon edges together while the glue dries. (sorry, I had a photo of this but it was blurry, new camera and all, still figuring it out!)
Step 4: Place the bow on your box. Thread stretchy cord through the loops and tie. If your box is cardstock, be careful not to pull the elastic cord too tightly. You can see mine is a wee bit to tight in the last photo.