to be utterly and completely full of shit
to speak to some one and clearly be bullshitting, but think your slick enough for them not to know...although in actual fact they are rolling their eyes at your stupidity.
person 1) did you talk to emily?
person 2) yeah what a loser... she said her parents are paying for a brand new benz for her bday
person 1) word? wait isnt she that same biatch whose parents dont own a car and is broke as hell?
person 2) yeah she was blowing rot all up in my ear, what a bullshitter,