Drink before bed (8)
I believe the answer is:
nightcap
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">drink before bed</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for nightcap that I've seen before include "something you get at the eleventh hour?" , "Last drink of the day?" , "A drink before bed, wearing nocturnal headgear" , "Old headgear" , "attire" .)