Some don't appear ready to be drawn (2,3)
I believe the answer is:
on tap
'ready to be drawn' is the definition.
(available to be drawn from a tap)
'some don't appear' is the wordplay.
'some' says the answer is hidden in the clue (some of the parts of the word are used).
'ON TAP' is hidden in the letters of 'dont appear'.
(Other definitions for on tap that I've seen before include "where C or H is seen?" , "Ready for immediate use" , "Readily available" , "Ready to be drawn off, say beer" , "Where to find a washer" .)