I was inspired by this pouch over at Jenni Bick:
This is what I made:
(sorry about the first pic being a bit blurry, unfortunately, I don't have another one...)
I cut a rectangle out of a piece of dark brown leather, folded it and stitched up the sides, as you can see in the second picture. I softened the corners of the part that folds over and punched a hole on each side. I then cut two strips of a lighter brown leather, put them through the holes, wrapped them around the pouch and knotted them for closure.
He liked it, so I am happy :) Hope you like it too!