I am kind of new to a Chat so not sure what I am doing, exactly, so if I have missed a thread, forgive me. I am on my 8th Toyota and happy to share that the problem with the bad cup holders in the Prius c Two is not new to me. I solved the issue in my RAV4 as I found something on the RAV4 Chat called a Drink Docker. It works GREAT in the Prius c Two as well. Now I don't have to worry about things spilling into what are, to me, essentially areas where liquids should not go! I know the design of the Drink Docker is pretty simplistic, but it saves me potentially a lot of money if my beloved Diet Coke were to tumble over while I am in traffic.
This almost feels like someone associated with the Drink Docker product trying to promote the item via social networking. Just a feeling...
I'll answer on behalf of the OP ... Personally, I have found that the size of the cup holder in the C is not friendly to the assorted things I might place there. A small bottle of commercially purchased water bounces around and tends to fall over and out during tight turns. Most of my portable water bottles are too thick around to fit in the space, and my daily water bottle fits loosely enough to rattle around (but not fall out). My guess would be that the OP has had similar issues and found in the Docker something which creates a perfect fit for whichever sized bottles/cups he/she uses on a daily basis.