Add all ingredients to crock pot.

Cook 4.5 hours on low.

After 4.5 hours, transfer meat to a plate or shallow bowl and shred with two forks. Use a slotted spoon, or tongs to transfer onions and peppers to bowl/plate as well. Drain liquid from crock pot. Return shredded steak, onions and peppers back to crock pot. Add 1 C cheez whiz, cover and cook for 15-30 minutes, until cheez has melted. Stir to combine and coat.

Roll mixture up in tortillas and serve.