What does "I taste sour in my mouth" mean in this context?
I heard the main character Dave said it in the 'Sorcerer's apprentice' movie.
D:This is not happening.. this is not happening. I taste sour in my mouth.
B: Take it easy, Dave. Deep breaths.

Question

What does "I taste sour  in my mouth" mean in this context?
I heard the main character Dave said it in the 'Sorcerer's apprentice' movie.
D:This is not happening..  this is not happening.  I taste sour  in my mouth. 
B: Take it easy, Dave. Deep breaths.

Answer

"I have a sour taste in my mouth"/ "it left a sour taste in my mouth" is a way to say you are left with a bitter feeling after something has happened.