Shitting your head out of your ass could refer to three things, either;
A, being so mad your head jets out of your ass;
B, wasting your time trying to shit your head out of your ass;
C, an incredible feat, such as lifting a car, watching a whole episode of Everybody Loves Raymond and laughing at it atleast twice, or beating up Chuck Norris.
A, "If I have to sit next to that bitch named Sophie AGAIN this year, I'm totally going to shit my head out of my ass.."
B, "World of Warcraft is like trying to shit your head out of your ass,"
and C, "Dude! What are you doing?!"
Dude- " I'm trying to make a myspace video of me shitting my head out my ass!"
"Shitting your head out of your ass?!"
Dude- "Shitting your head out of your ass."
A phrase used to refer to someone who is talking so much shit.
Koko: Have you seen Lulu? That girl need to know when keep her ugly self away from my man, before she gives him STDs.
Oreo: How do you know she's hitting on you guy?
Koko: Because my friend heard from her sister's friend's boyfriend's lab partner. Duh
Oreo: YOU DON'T EVEN HAVE EVIDENCE! You're spitting ass! SPITTING SO MUCH ASS!
the act of doing absolutley nothing. sitting on ones behind (or ass) instead of doing somthing productive, such as going out at night, going to work, or simply moving ones pathetic body from their couch.
Just because I am able to figure out shit above and beyond does not mean that I should be required to so that everyone else can sit ass. I am very good at sitting ass, too.