On Thursday, October 19, 2017 at 1:38:26 PM UTC-7, wrote:
Has anyone installer a cup holder on their glider? Pictures?

The luggage shelf on my glider holds a latte while prepping the glider on the ground. So does the rear of the trailer.

You really mean while flying? How much fun do you want other pilots to make of you?

What you should be looking at, assuming you want to fly cross country, is where to place Camelbak or similar hydration packs. How to route the drinking tubes, retain them so you don't sit on them, etc.