Here are pics of my thermal quilted drink wrap that I made last weekend. The concept is common, but this design is my original, and I made my own template by wrapping a cup and drawing the pattern, then transferring it to cardstock:
It's fully adjustable from 16-48 oz. cups. I added the little vinyl pockets to hold photos, drink recipes, or even a name.
Future ones will have a regular fabric cord with sliding stop closure - much faster than tying it each time. And, the button will be matched to the fabric design.