Here's a quick way to carry several cans/bottles easily using the Furoshiki methods using a square cloth of about 20 inches to a side.
Step 1: Layout Your Cloth and Beverages of Choice.
You don't have to use Diet Cokes and a ratty old dish towel. You can use any beverage can/bottle or square cloth (e.g. RootBeer and a nice silk square of cloth). You could even use Diet Pepsi....but only if you're really desperate!
Step 2: Set Your Cans/bottles in Position
What you're wanting to do is set them a little bit apart and putting in a third can does it just right. Note: if you are doing just two cans/bottles; it might be better to set the two cans together (centered on where the middle can is in the pic below) and then tipping them away from each other. But this way worked for me when I was dealing with four cans.
Step 3: Roll Up Your Cans....there's a Bon Mot There Some Where...hmmmmm
Pull out that middle can and then flip the corner of the cloth up over the cans that were flipped on their side.
Now set the remaining cans/bottles (if any) next to the ones on the cloth and start rolling diagonally.
When you've rolled them up pick up the two corners carefully and bend the cloth in the middle so that you make a delicious Diet Coke 'U'.
Step 4: Tie Up Your Stash
Now just take the ends and tie an nice little square knot and there you have it.
If you need a good solid loop at the top of the stack, you can do it this way.
Make an overhand knot (that's what you call the first knot you use when your tying your shoes). This will help keep the cans down away from the top of the loop and make it more secure if your clothe was a little less than square. Now go almost to the end of your 'tails' and tie a square knot.
When I used this the other day I made it with the first method and then tied the whole sling to the outside of my messenger bag (which didn't have enough room to carry them all) and it held together fabulously....clever Japanese!