When creating a Twitter Application the default setting causes sign in to require the user to re-authorize every time the user is redirected to the twitter website.

To fix this all you need to do is sign into the Twitter dev website: http://dev.twitter.com

Navigate to your application and go to the Settings tab:

Navigate down the page until you get to Application Type:

Tick this setting and save, next time you sign in with twitter the app will automatically redirect back to the website if your app is already authorized.