The bonus he received in addition to his salary was pure 'gravy'.
They're trying to get on board the 'gravy train'.
a 'gravy' boat [=a container for serving gravy]
(..) - So, what do you think? - You mean, the last time I laid some pipe? The last time you went 's? The percy in the playpen.. - It's personal. - Wallpapered the closet, passed the gravy. - Went heels to Jesus. - Oh, make loves. Well, it's just, sex. Uhm.. Three weeks ago, yeah. (..)2009 Zombieland