Duck or swallow? (3,4)
I believe the answer is:
get down
I believe this clue is a double definition.
'duck' is the first definition.
(I've seen this before)
'swallow' is the second definition.
(I know that swallow can be written as get down)
'or' acts as a link.
(Other definitions for get down that I've seen before include "See feathers, > alight" , "you could - from duck" , "Swallow" , "Dismount, alight" .)