Doritos Tacos, also known as Doritos Locos Tacos, is a product of Taco Bell restaurants, which consists of a taco shell made of Doritos brand tortilla chip ingredients in Cool Ranch, Nacho Cheese and Fiery flavors.
After noting that Doritos Tacos are only available for a limited time on a billboard before seeing that Tom Tucker is contemplating suicide in "The New Adventures of Old Tom", Peter is seen licking off his fingers from the orange cheese powder used in the making of the Doritos shell, having made a stop for the tacos before arriving for Tom.