Or go back and play the guitar on the platform (7)
I believe the answer is:
rostrum
'the platform' is the definition.
(rostrum is a kind of platform)
'or go back and play the guitar' is the wordplay.
'go back' shows that the letters should be reversed in order.
'and' says to put letters next to each other.
'play the guitar' becomes 'strum' (I've seen this in another clue).
'or' reversed gives 'ro'.
'ro'+'strum'='ROSTRUM'
'on' is the link.
(Other definitions for rostrum that I've seen before include "Rum rots (anag)" , "beak" , "Platform for public speaking" , "Conductor's dais" , "Podium" .)