One's party piece - Idioms by The Free Dictionary
(one's) party piece (redirected from one's party piece)
(one's) party piece
Something one is able to do that is especially funny, odd, or otherwise entertaining. My party piece has always been my ability to roll my eyes in different directions.
your ˈparty piece (British English, informal) the same song, poem, trick, etc. that you often do in order to entertain people at parties: His party piece is to stand on his head and drink a glass of water.