Some after sex that's quick (5)
I believe the answer is:
terse
'quick' is the definition.
'some after sex that's' is the wordplay.
'some' indicates the answer is hidden within the clue (some of the parts of the word are used).
'TERSE' is hidden within 'after sex that'.
(Other definitions for terse that I've seen before include "Trees (anag.)" , "Brusque and curt" , "Brusque among trees" , "Compact" , "Curt, laconic of speech" .)