Recline - swallow concoction beforehand (3,4)
I believe the answer is:
lie down
'recline' is the definition.
(I've seen this in another clue)
'swallow concoction beforehand' is the wordplay.
'swallow' becomes 'down' (I've seen this before).
'concoction' becomes 'lie' (I've seen this in another clue).
'beforehand' means one lot of letters go next to another.
'down' put after 'lie' is 'LIE-DOWN'.
(Other definitions for lie down that I've seen before include "Relax" , "Recline" , "Assume a reclining position" , "joining rest" , "Rest (with or without sleep)" .)