Cask tap (6)
I believe the answer is:
spigot
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">cask tap</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for spigot that I've seen before include "Plug for cask vent" , "Got sip? (Anag)" , "Bunghole plug" , "Tap fitted to a cask" , "Small plug for cask" .)