After gulping in, answer royal with care (13)
I believe the answer is:
painstakingly
'after gulping in' is the definition.
Both the answer and definition are adverbs. Perhaps you can see an association between them that I can't see?
'answer royal with care' is the wordplay.
'answer royal' becomes 'takingly' (I can't explain this - if you can you should believe this answer much more).
'with' means one lot of letters go next to another.
'care' becomes 'pains' (I have seen 'Great care ' mean 'pains' so perhaps 'care' could also mean 'pains').
'takingly' after 'pains' is 'PAINSTAKINGLY'.
Can you help me to learn more?
(Other definitions for painstakingly that I've seen before include "In meticulous style" , "with great care" , "In a most careful way" .)