Sebastian embracing King Charlie (4)
I believe the answer is:
coke
'charlie' is the definition.
(I know that charlie can be written as coke)
'sebastian embracing king' is the wordplay.
'sebastian' becomes 'coe' (I can't justify this - if you can you should believe this answer much more).
'embracing' indicates putting letters inside.
'king' becomes 'K' (abbreviation for king in chess).
'coe' enclosing 'k' is 'COKE'.
Can you help me to learn more?
(Other definitions for coke that I've seen before include "Residue from coal used as fuel" , "Solid fuel - drink - drug" , "'Soft drink and hard drug, in short (4)'" , "Substance left after gas and tar have been extracted from coal" , "Furnace fuel" .)