Step 1: Layout your cloth and beverages of choice.
Step 2: Set your cans/bottles in position
Step 3: Roll up your cans....there's a bon mot there some where...hmmmmm
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
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!