Pet swallow (4)
I believe the answer is:
neck
This clue is a double definition.
'pet' is the first definition.
(I know this)
'swallow' is the second definition.
(I know that swallow can be written as neck)
(Other definitions for neck that I've seen before include "Body part associated with impudence" , "top of bottle" , "jowl?" , "Kiss amorously" , "Part of body connecting head and torso" .)