Handful of Concepts - Bottle Brolly.

"Beverage bottle umbrella."

Now, we've all heard of those cocktail umbrellas which are designed for both decoration and to keep your drink slightly cold. Why not get a miniature umbrella which is attached to the top of an L shaped plastic rectangle, with a clip big enough for the radius of the bottle at the bottom end of the L. The umbrella would be big enough to fit over the bottle giving it some shade on a sweltering hot day. Its just another way to keep your drink cool and out of the sunlight, as well as to keep the wasps and flies at bay from landing on the rim of the bottle.
As we all know how annoying that can get.