idiom. This is what happens when you end up mired in conversation with one or several shit-for-brains--especially those who are so dumb, they got shot in a knife fight.
Real citation: "Suddenly she spies Jess coming toward them. Marissa needs to say nothing except "Hey, Jess," but she already popped a brain cell trying to remember what band they're even there to see, and so blanks on what to say. She makes Summer initiate conversation. "Oh my God, Jess, remember me?" Summer gushes, hugging her and reminiscing about their old tap and jazz days. She then does a cute little tap move. Marissa has sufficiently recovered long enough to offer this clever rejoinder: "Don't mind my friend. She's really...really stoned." Summer shoots her a glare, then recovers a split-second later -- great timing by Rachel Bilson -- and drawls, "Tooootally. Very, very high. Isn't this place, like, so visual?" Jess looks like she's stepped in a pile of moron."
(Heathen, "The O.C. Confidential," page 8, Television Without Pity, http://www.televisionwithoutpity.com/story.cgi?show=112&story=7869&page=8&sort=&limit=)
Made-up citation: “You can’t step in the same river twice, and you can’t walk three feet in this country without stepping in a steaming, staggering pile of moron. God bless America.”