Sentimental stuff after father gets snack (7)
I believe the answer is:
popcorn
'snack' is the definition.
(I know that popcorn is a type of snack)
'sentimental stuff after father' is the wordplay.
'sentimental stuff' becomes 'corn' (corn or corniness can mean sentimental material).
'after' means one lot of letters go next to another.
'father' becomes 'pop ' (pop is a kind of father).
'corn' put after 'pop' is 'POPCORN'.
'gets' is the link.
(Other definitions for popcorn that I've seen before include "Popular snack in the cinema" , "Kernels exploded by heat" , "Burst maize" , "stuff that may accompany film" , "Feature accompaniment" .)