I stopped by Circle K to answer this important question. Here's photo evidence:
Here's a picture of my cupholder and Hydroflask that I mentioned. I usually hold the Hydroflask in my lap. I only put it in the cup holder when I leave it behind while shopping, etc.
It's the "Kemimoto Car Cup Holder Expander Compatible with 26/30/36oz Yeti, 32/40oz Hydro Flasks, 20/32/48oz Nalgene, Large Cup Holder Adapter for Car Fits for Universal Vehicles, Golf Carts, UTVs, RVs, Trucks" on Amazon for $16.