He is a sexist 'pig'. = He is a 'male chauvinist pig'. [=he is a man who thinks women are not equal to men]
The train station will be renovated 'when pigs fly'. [=it will never be renovated]
“This time I think he'll ask me to marry him!” “Yeah, and 'pigs might fly'.”
(..) And scene. Shoot. - What are you doing? - God! Rory! Announce yourself! - Were you brushing dirt under the sink? - No, I'm brushing crumbs under the sink. You're a pig. You're just learning that? Why are you here, anyway? Crabby and dirty. I thought you were going to hang (..)2004 TvShow: Gilmore Girls Title: The Nanny and the Professor Season: 4 Episode 10
(..) It is a unique substance unto itself, like Velveeta or plutonium. - You're not even going to try it? - I'll pass. - I'll try some. - Take the one with the little pig on it. Thank you. We got the pigs for you and the bunny for your mother. - You got me bunnies? - They're for whomever now. (..)2004 TvShow: Gilmore Girls Title: The Nanny and the Professor Season: 4 Episode 10