Calm down, silly sausage! (7)
I believe the answer is:
assuage
'calm down' is the definition.
(assuage can mean to calm down or relieve)
'silly sausage' is the wordplay.
'silly' indicates an anagram.
'sausage' is an anagram of 'ASSUAGE'.
(Other definitions for assuage that I've seen before include "Mollify" , "allay hunger perhaps" , "Make less severe, pain or hunger, say" , "9 across (anag)" , "Soften, pacify" .)