Blowin Doo-Doo
This is when someone is lying, or making threats that they are not able to back up.
1st person: Man, did you hear what Jennifer was saying about Jim. I didn't know that about him.
2nd person: I wouldn't believe anything she said. Jen is constantly blowin doo-doo.
2nd person: I wouldn't believe anything she said. Jen is constantly blowin doo-doo.