Coffee cup holder

[Globetrotter.uk]

I was out at the weekend with some coffee addicts and one of the ladies wants a holster to hold a takeaway cup for her rucksack. Anyone got any ideas.

 

[Shewie]

What size cup are we talking, something like a medium sized Starbucks cup ?

I'd look at packaging around the kitchen and see if you can find a tube the right size, something like a Vanish tub, coffee can, milk powder bottle etc etc.