Hair around mouth that could form a wet oscular mush (6,9)
I believe the answer is:
walrus moustache
'hair around mouth' is the definition.
(type of facial hair)
'that could form a wet oscular mush' is the wordplay.
'that could form' indicates an anagram.
'a'+'wet'+'oscular'+'mush'='awetoscularmush'
'awetoscularmush' anagrammed gives 'WALRUS MOUSTACHE'.
(Other definitions for walrus moustache that I've seen before include "Hairy thing" , "hair" .)