Sauce regularly guzzled by that woman with meat, unfortunate mistake (4,2,3,6)
I believe the answer is:
slip of the tongue
'unfortunate mistake' is the definition.
(a slip of the tongue is a mistake when speaking)
'sauce regularly guzzled by that woman with meat' is the wordplay.
I cannot quite understand how this works, but
'sauce' could be 'lip' (I've seen this before) and 'lip' is located in the answer.
'regularly' could be 'oft' (I've seen this in another clue) and 'oft' is found in the answer.
'woman' could be 'she' and 'she' is present in the leftover letters.
'meat' could be 'tongue' (type of meat) and 'tongue' is located in the answer.
No letters remain.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for slip of the tongue that I've seen before include "mistake one hears" , "vocal error" , "Error in words" , "a small error" .)