How would I go about making my poster for a wwe match?

I was going to use that poster paper or whatever it's called that you can buy from the dollar store but then when it rolls up and you spread it apart it'll just roll back and it wont stand straight up when i hold it with one hand and this sign must, i repeat, MUST, be seen on TV because this is just pure geniuous. Anyways how do I make it stand up or what do i use or whatever?