Jokingly said 'Swallow' (6)
I believe the answer is:
ingest
'swallow' is the definition.
(I've seen this before)
'jokingly said' is the wordplay.
'jokingly' becomes 'injest' (I've seen this before).
'said' indicates a 'sounds like' (homophone) clue.
'injest' is a homophone of 'INGEST'.
(Other definitions for ingest that I've seen before include "Absorb, assimilate" , "How to take courses" , "Take (food) into the body" , "Swallow -signet (anag)" , "Swallow, absorb" .)