Stopper was first to be handled badly (7)
I believe the answer is:
bungled
'handled badly' is the definition.
The answer and definition can be both to do with social activities as well as being past participle verbs.
Perhaps there's an association between them I don't understand?
'stopper was first' is the wordplay.
'stopper' becomes 'bung' (bung is a kind of stopper).
'was first' becomes 'led' (to lead is to go first).
'bung'+'led'='BUNGLED'
'to be' is the link.
Can you help me to learn more?
(Other definitions for bungled that I've seen before include "mismanaged" , "Spoiled through incompetence" , "Slipped up there" .)