Up her own arse
Heard in Dublin
Describes a girl who is better then everybody else. Can be applied to a bloke, "he's up his own arse" - but usually a girl.
See her there, that one wouldn't shag you in a fit. She's up her own arse
Observe her over there, that young lady would not grant you any attention whatsoever for love nor money. She holds herself in quite absurdly high regard.