Okay, this is going to sound really stupid

I want to make Summerlin some leashes to match her dresses. Here's the thing - the only leashes I have are from places like PetSmart, the nylon or leather kind. I know it is possible to make leashes out of material or ribbon - I have seen them, I am just not sure of the way to do it. Does anyone here make their own leashes? I would think that if I sew the ribbon down both edges, with it folded in half, that part would work, but it would not be as strong as a regular leash... how do I overcome that part of the problem? Any suggestions would bre greatly appreciated!