What digital artist does with eg bit of whisky, say, and beer, drinking a mixed gin (6-8)

'what digital artist does' is the definition.
(painting with digits)

'eg bit of whisky say and beer drinking a mixed gin' is the wordplay.
'eg bit of whisky say' becomes 'finger' (finger can mean a small alcoholic drink).
'and' is a charade indicator (letters next to each other).
'beer' becomes 'pint' (beer is typically served by the pint).
'drinking' indicates putting letters inside (inserted letters are consumed or drunk).
'mixed' is an anagram indicator.
'pint' placed around 'a' is 'paint'.
'gin' is an anagram of 'ing'.
'finger'+'paint'+'ing'='FINGER-PAINTING'

'with' acts as a link.