Fizzy drink for dad (3)
I believe the answer is:
pop
I believe this clue is a double definition.
'fizzy drink' is the first definition.
(I've seen this before)
'dad' is the second definition.
('pop' can be a synonym of 'dad')
'for' acts as a link.
(Other definitions for pop that I've seen before include "Soft drink - father - music - light explosion" , "Explosive sound; drink" , "'American Dad'!" , "Explode; Eton society" , "US fizzy drink and type of music" .)