I Guess You Had To Be There

So I was reading this blog a while back, and I came across an expression I never heard before. It was "Grinning like a possum eating shit off a hairbrush." This prompted a flurry of questions in my head:
1) What??
2) Why is the possum eating shit?
3) And why is he grinning about it?
4) Does shit taste better to a possum when served on a hairbrush?
5) And why is shit on a hairbrush to begin with?
I have no answers for any of it.
Fast forward to last Monday, when Max and I were at Red Robin having burgers. I had just recounted the above story to him, and he was as mystfied as I was. So we are sitting there and at Red Robin they always put fun stuff on their coasters:




So, fresh off the above conversation, I write this:




I show it to Max, and after we debate whether or not "eat shit off" is a verb (I say it is), he grabs the pen and writes this:




Which prompts huge fits of laughter from both of us. I tell you, laughs come cheap in this family. How fortunate that we are so easily entertained!