(definitions from Dictionary.com)
37. Cards. to expose (a card) in the process of dealing.
Flashing cards! Do you love or hate when dealers do that? Flash
writers seem to hold their cards closely, refusing to let readers see anything
until that final twist at the end: Oh my God! I haven’t told you yet. But that
girl I’ve been dating throughout the story. She’s really an alien! I bet you
didn’t see that coming.