(Burning Ring of Fire) Do you really need an explanation? Runny diarrhea that burns as it exits. This often happens the morning after spicy food, or Chinese food (Chinese fireball). It really is self explanatory.
"Your mouth is writing checks your ass can't cash," is something TV Dr. Phil McGraw's father said to him as a boy when he would voice wild plans or notions. It means that talk is cheap relative to performance, or that promising something and delivering on it are two different things. A phrase similar in meaning is "Money talks, bullshit walks."