Cording (approximately 36" - 50", or 1 - 1.4 yards) Scissors Superglue
Step 1:  Wrap cording around your waist where you would like your belt to sit to measure how much cording your tail belt will require.
Step 2:  Add an extra 12" onto that measurement to provide sufficient room for a loop and tying.  A bit of superglue at both ends of the cut cording will harden the fibers and prevent unraveling.
Step 3:  Hold the cording at one end, measure four inches down, and create a loop, securing it with superglue.
Step 4:  Slip the non-looped end of the cording through your tail's loop.
Step 5:  Use any extra cording to tie a knot through the tail belt loop.
Step 6:  Once the knot is tied, cut off any excess cording (and secure the newly cut end with superglue) so that your tail belt is the perfect length!
Wear rubber gloves and safety goggles when working with superglue (my favorite brand is "Surehold Plastic Surgery" found at ACE Hardware).  Superglue actually releases visible fumes that can severely irritate the eyes (I was once unfortunate  enough to have this happen to me).  If your fingers or skin become accidentally stuck despite your precautionary measures, a product called "Unglue" or "Uncure" found at local Hobby Shops will help unstick your skin. I always have a bottle  on hand when working on projects that require superglue.