I printed this using Elegoo PLA+, but most anything should work. I contemplated TPU and may test with that later, but the PLA was already loaded in my printer and worked just fine. The model is not perfectly fit to the bottle, but from my testing and use of the bottle, it wasn't a problem, and the ring stays where you put it. Making the model perfectly form-fitted, given the bottle's shape, seemed like more effort than it was worth to hold a straw. As is, everything holds like you need it to and you have to really look to see the gaps between the ring and the bottle.
Please leave feedback or post a make if you find anything that can be improved. I am always looking to get better.
The author marked this model as their own original creation.