1. When you are in a serious amount trouble.
e.g. "Im in deep
shit."
2. A seriously dark or over thought idea.
e.g. Person 1: "Life is completely pointless"
Person 2: "Wow, thats some deep
shit."
3. When you are in the middle of a
shit and you start going into deep thought and all ignore around you, eventually realise you spend way too long on the toilet then you should have.