Go wild in carnival location, tucking into shrimp (3,4)
I believe the answer is:
run riot
'go wild' is the definition.
(I've seen this in another clue)
'carnival location tucking into shrimp' is the wordplay.
'carnival location' becomes 'Rio' (Rio de Janeiro is famous for its carnival).
'tucking into' is an insertion indicator.
'shrimp' becomes 'runt' (synonyms).
'rio' inserted into 'runt' is 'RUN RIOT'.
'in' is the link.
(Other definitions for run riot that I've seen before include "behave in unrestrained way" , "Go wild" , "Go on the rampage" , "Go berserk" , "Behave unrestrainedly" .)