Drink them after party and irritate spoilsport
I believe the answer is:
dog in the manger
'spoilsport' is the definition.
(thesaurus)
'drink them after party and irritate' is the wordplay.
'drink' becomes 'gin' (gin is a kind of drink**).
'after' is a charade indicator (letters next to each other).
'party' becomes 'do' (do is a kind of party).
'and' says to put letters next to each other.
'irritate' becomes 'anger'.
'gin'+'them'='ginthem'
'ginthem' after 'do' is 'doginthem'.
'doginthem'+'anger'='DOG-IN-THE-MANGER'
(Other definitions for dog in the manger that I've seen before include "selfish hoarder" , "error in farmyard?" , "One not letting others use what they themselves have no use for" , "possessive type?" , "One who won't let others enjoy what they have no use for" .)