Awful cheek pinching line, so barrack (6)
I believe the answer is:
heckle
'barrack' is the definition.
(I've seen this before)
'awful cheek pinching line' is the wordplay.
'awful' indicates an anagram.
'pinching' indicates putting letters inside (taking inside).
'line' becomes 'l' (used when specifying particular lines from a poem).
'cheek' anagrammed gives 'hecke'.
'hecke' placed around 'l' is 'HECKLE'.
'so' is the link.
(Other definitions for heckle that I've seen before include "Shout disruptively at performer" , "Verbally interrupt performer" , "Mock or harangue speaker from crowd" , "Harass a speaker" , "Shout down (a politician)" .)