Tug back stomach (3)
I believe the answer is:
gut
'stomach' is the definition.
(I've seen this in other clues)
'tug back' is the wordplay.
'back' is a reversal indicator.
'tug' back-to-front is 'GUT'.
(Other definitions for gut that I've seen before include "Food processor" , "The stuff of a violin string" , "Stomach, maw" , "Remove the insides, of a fish say" , "Evidence of heavy drinking" .)