Well, I may have the perfect answer to this problem!!
..The Cup Snug!
Knitted by my auntie and embellished with beads and sequins by my sister, this is our first prototype. Now, I can't guarantee that it will stop your cuppa going cold but it might help keep it warm for that little bit longer! And it will definitely liven up a boring paper cup from your fave coffee shop! We are also working on a mug snug which will accommodate mugs with handles.
Would you like to see this and more like it in my shop??