Generally someone whose actions would lead one to believe that the person is using crack cocaine due to the stupidity or messed-up-ness of their actions.
Used to describe something stupid, messed up or to express frustration with something

A pick me is a woman that is willing to do anything for male approval. She will embarrass or throw other women under the bus to achieve this goal. The unfortunate thing about a pick me is usually the men they are trying to seek approval from are of poor quality and treat women badly, leaving little real benefit for the pick me.

1) Unbelievable; insane.

2) Good, bad, or extremely out of the ordinary.

Note: Both definitions an be used in both positive and pejorative sense.

if something is mad, bad or just plain wrong, it can be described as "on crack", or, for added emphasis, "so on crack".

Also used to describe a person on serious drugs.

Also used to describe a person using Crack-Cocaine.