Spin out good man's gag (7)
I believe the answer is:
stretch
'spin out' is the definition.
(thesaurus)
'good man's gag' is the wordplay.
'good man' becomes 'st'.
'gag' becomes 'retch' (I've seen this before).
'st'+'retch'='STRETCH'
(Other definitions for stretch that I've seen before include "Tax" , "Make demands on; lengthen" , "Elasticity, prison term" , "Continuous expanse/period" , "time at Pentonville?" .)