I'm having trouble remembering this movie - or it might have been a TV show - where this guy eats the anniversary tier of a wedding cake and then replaces it in the freezer with dog poop. Maybe the guy was living with a couple of friends and came home drunk and did it without remembering doing it, or he did it out of spite. I know I didn't dream it, because my fiancée corroborated the story. She mentioned 'IASIP', but I don't think that's right. What movie or television show did this come from?

The only thing I can recall that is ANYTHING like this is American Wedding. The two geeks (band geek girl) who met in the first one are getting married, and their douchebag friend Stifler is holding dog poop on a little paper cuplike thing (I cannot remember the reason for this), and this lady thinks it's a chocolate and wants to eat it, and the only way to stop her is by shoving it into his own mouth. Sorry from the hazy description you gave, this is the only thing that comes to mind.