grave mouth
The inability to taste or detect a flavor that may range anywhere between mild to extreme, such as sour, sweet, or spicy. You either have hypogeusia, ageusia, or your taste buds have been dead for years.
Shayne: What a fine meal.
Garrett: How are you not tasting the malic acid?! It's so supposed to be sour!
Shayne: I have grave mouth.
Garrett: How are you not tasting the malic acid?! It's so supposed to be sour!
Shayne: I have grave mouth.
digging your own grave with your mouth
A metaphorical phrase to describe the common practice of eating yourself to death.
Well my friend, it seems that you are highly unable to stop digging your own grave with your mouth!