A variation on the Dirty Sanchez sexual move, where the first participant eats a box of Lucky Charms 2-3 hours beforehand. This results in a more colorful and amusing feces.
Josh (on the phone): Hey girl, I was thinking we could try out the Mexican Rainbow
Girl: Sure!
Josh: Awesome, let me just go to Walmart and pick up some Lucky Charms. Ben's going to be so jealous when he finds out!
What you're about to, after you can't find your keys, and your laptop is in your car, and you don't have enough money to call a locksmith.
"Thomas Beauvais is about ready to 405 rainbow frisbie. I can't find my keys, and my laptop is in the car, and I don't have enough money to call a locksmith."