When someone who doesn't appear to know anything about sex surprises you by rocking your sexual world and giving you an amazing orgasm.
"I kind of hooked up with Lenny this weekend." "You mean the band geek? Really?" "Yeah, but he knew how to do some things that i never would have guessed. He gave me a flabbergasm."
"Upon seeing a fellow human in a grocery store, wearing a yellow unitard with no underwear, sporting a giant moose knuckle has left me in a state of flabbergastion."
"People that act like douchebags often leave me in a state of flabbergastion."