Go to our redemption page.
Submit your username, summoner name, server region and the stream code.
Why couldn't this be on your official web page? We're supposed to gladly associate our username/summoner name on any random web page now? I always thought the user name being left out of the equation, provided at least some security for users. Make the loss of an account slightly more difficult.
But I guess I'll trust some random guy, on a forum, who claims to be from Riot, to give me a special summoner icon, by submitting my login name w/o password, to some random webpage.