1) An expression used to indicate that you don`t give a fuck about what the person is saying.

2) An expression used as non-sense towards someone whether they are in a car driving and you are walking on the sidewalk or someone in the hallways of a school.

3) An expression of non-sense that can be said in a high pitched voice or said like you're a dinosaur.

4) Using a crab as example: hold a crab up to someone and pretend like the crab is saying RAHHH!