This word has many meanings.
1) One meaning is associated with the site calmdownnpushit.com when it is use to tell someone to calm down and move on.
2) Another way it can be used is by use of an interjection. It is a way to counter someone.
1) Bob: Yo, I failed my test.
John: Calm the fuck down and pushit, u bitch
2)Ho: ayo check out that inter-racial couple over there
Pete: Pushit........ (disgusted face)