Found a way to have a 5th and 6th cupholder.

I found a simple but effective way to secure water bottles to the center console floor area using a bungee cord.
We use our Prius for very long road trips for our family of 4. The kids use the rear cup holders, and we like to have coffee in the front cup holders. The bungee cord method allows us to secure our yeti bottles nicely to the footwell/center console. Great solution for the long road trips if you want coffee and water up front!!