This song is called "Douche or Turd?". I originally heard it on the 2004 election episode of South Park, where the boys had to vote on which was a better school mascot - a giant douche or a turd sandwich. Here are the lyrics:
Let's get up and vote! Let's make our voices heard! We've been given the right to choose between a douche and a turd. It's democracy in action. Put your freedom to the test. A big fat turd or a stupid douche? Which do you like best?