Small quantity of spirits (6)
'small quantity of spirits' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for noggin that I've seen before include "Snifter" , "Small measure of spirits or mug" , "Peg" , "Small measure of liquid" , "Head - tot" .)
(Other definitions for dram that I've seen before include "A wee spirit" , "slug" , "Tot of whisky" , "Short" , "Measure of Scotch" .)