1 definition by Biros

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!
by Biros August 20, 2008
Get the Mexican Rainbow mug.