A run of luck, often in reference to money (perhaps related to the silver line that runs through many banknotes).
After selling his idea to all the top Hollywood studios, Paul's silverstreak continued when he married a Playboy bunny.
Being constantly dehydrated due to regular consumption of caffeine containing drinks.
"No wonder she looks like a wrinkly prune. She's totally teahydrated from being jacked up on Earl Grey."