Can be used after swear words to make them less severe. The seriousness of the explietive and the sheer niceness of the word "muffin" cancel each other out, and the recipient of the full phrase will know that the explietive is not being used entirely seriously.
You just ate the last ice cream, you complete and utter cuntmuffin!
A game consisting of a group of guys circle jerking onto a muffin which is located in the center of said circle jerk. Players compete by jerking their member until they ejaculate their "frosting" on the muffin. The last jerker to frost the muffin receives the pleasure of eating said muffin, along with all its frosty goodness.
Tom: I'm bored
Kyle: I have an idea! lets play muffin!!!