Opening heart, perhaps, and play this (5,5)
I believe the answer is:
mouth organ
'play this' is the definition.
(a mouth organ is a type of instrument)
'opening heart perhaps' is the wordplay.
'opening' becomes 'mouth' (mouth is a kind of opening**).
'heart perhaps' becomes 'organ' (heart is a kind of organ).
'mouth'+'organ'='MOUTH-ORGAN'
'and' is the link.
(Other definitions for mouth organ that I've seen before include "tongue?" , "Harmonica" , "I can make music" , "What produces musical sounds" .)