One of the most delicious dishes in Mexican cuisine is tacos de lengua, or beef togue tacos. The meat is so soft and has such a delicate flavor that it is only steamed and put on a tortilla, topped with jardín (chopped cilantro and diced onion), lime and salsa verde.
The expression de lengua me como un taco literally means "of tongue I shall eat a taco." It is used to express disbelief on someone's claims. It comes from the allusion to ser lengua, or to be a person characterized for saying things that are usually not true. In this context a person that is lengua is also an hablador, a liar.
Luis: ¿A quién crees que vi en Acapulco?
Mario: Me vale madres.
Luis: A Bernie Madoff, el estafador. Estaba esquiando en Puerto Marqués.
Mario: De lengua me como un taco. Pinche hablador.
Luis: Guess who I saw in Acapulco.
Mario: I don't give two shits.
Luis: Bernie Madoff, the scammer. He was waterskiing in Puerto Marques.
Mario: You are not more full of shit because your not taller.