Go too far again and bash (6)
I believe the answer is:
overdo
'go too far' is the definition.
(thesaurus)
'again and bash' is the wordplay.
'again' becomes 'over' (as in the phrases 'start over' and 'start again').
'and' is a charade indicator (letters next to each other).
'bash' becomes 'do' ('do' can be a synonym of 'bash').
'over'+'do'='OVERDO'
(Other definitions for overdo that I've seen before include "Carry to excess" , "Cook wrongly" , "Exaggerate, go too far" , "Exaggerate; use too much of" , "Maybe burn" .)