Recently I received this faux leather jacket, and I thought it's a good opportunity to show how I make my flasks. I used a piece of a sleeve with the zipper in it, but a plane piece of material will do as well. The only two dimensions you need to take is the length from the bottle neck to the bottom plus half of the bottle thickness, and the second one is the length around the bottle. Try your material for how much it stretch and make the allowances. First of all, sew the bottom part of wrapping as shown on the picture (pull the material corners inside) and then sew all the way up to the top. Use any seam you prefer, there's a lot of tutorials on the internet. Then push together the leather near the bottle neck and mark the future seam. Then sew it. Insert eyelets and attach the strap and here it is. Usually, I remove all the labels from the bottle but in these case where we have the zipper in front of flask I thought it would be a good idea to left it all there so that you could strip the faux leather off and discover more about what inside. And yes it was a bottle of vodka.