How can I straighten a collar?

How can I straighten a collar that sits differently on each side of a shirt? I like to wear the shirt with the top button unbuttoned. The problem is that the top of the shirt falls to the right and takes the collar with it. The collar on the left sits vertically with the shirt in a neat fashion, crisp with the collar fold. The collar on the right fades off horizontally and has pulled the collar crease down so that the collar seems larger. Any suggestions would be appreciated.