When you accidentally merge words together, swap the first letter, or when you can't decide on which word to say so you say both, merging them. It can be because you're nervous, drunk, or just not paying attention to what you're saying. Merd worge is a merd worge in its self.
Joe: Where were you last night, Steve?
Steve: I had diolent viohhrea...
Joe: Merd worge!