I'm surprised when I ran a search on this that there is no such topic. The world in fantasy books is based mostly on their own versions of English sayings.
It would be very nice to have Sirius wide common sayings, like
"What's wrong? You look like a nomad has crawled up your arse."
"He ran like nomads were on his tail."
"Sweet Gaia!"
"May the black hole swallow you pirate!"
Come on. It's your turn. I'm looking for a Disco substitute for noob or morons. That would be so nice to say in NY. "Get a load of this guy he's like..."
I say "Good Queen" instead of "Good Lord" with my BPA sometimes. As well, when he's enraged and wants something he'll begin the sentence with "In the name of the Queen!"
Also, my Junker says "Scrap!" (instead of, you know, drop the s). He tends to use it in a positive way as well though, since he's scrap metal addicted.
Oh, and I just got an idea for a Blood Dragon battle cry. How about "For Hideyoshi!"? (May be too unkown though...)