Samuel swallowing ecstasy in joint (4)
I believe the answer is:
seam
'joint' is the definition.
(I know that seam is a type of joint)
'samuel swallowing ecstasy' is the wordplay.
'samuel' becomes 'sam' (I can't explain this - if you can you should believe this answer much more).
'swallowing' indicates putting letters inside.
'ecstasy' becomes 'E' (informal term for the drug).
'sam' placed around 'e' is 'SEAM'.
'in' acts as a link.
Can you help me to learn more?
(Other definitions for seam that I've seen before include "Stitched joint" , "Sewing join" , "Stratum of ore or coal" , "Line of sewing - stratum of coal" , "Joint between two edges" .)