Crinkle your nose and you think your cards stink. Interlocking fingers are a sign you're worried. Lean in toward the pot and you probably think it's yours already.

"Your lips tighten when you're stressed," Navarro, 54, told a concerned Margaret Gast, a 50-year-old ice skate shop owner from Houston, who he pulled off the felt for some one-on-one advice. "You're doing it when I'm talking right now. You don't need to tell me, I know."

Gast was surprised that she gave so much away.

"He said it would be better if I just folded my hands and held them over my lips," said the amateur who hoped to play in the World Series of Poker ladies-only event on Sunday. "I'll use that."

Online poker players have come out of the woodwork to win the World Series' $10,000 buy-in main event — including three of the last four champions.

But Navarro, a 25-year veteran of the FBI who still teaches nonverbal communication skills to agents in Quantico, Va., says there is more to the game than betting and the cards.

Signs of strength can be a good indication to fold, while a person displaying weakness is a ripe victim for a bluff.

A common tell of supreme confidence is the steeple, he said. When players brings their hands together so the fingertips and thumb touch with the palms apart, it may be time to give up.

"Someone has the winning hand and they'll steeple," he said. "And they don't realize they're doing it. A lot of people have been taught nonverbal behavior doesn't have meaning or that you can't tell what people are thinking. That's nonsense."

In a real-life example, FBI agents investigating an espionage case had arrested one person who they believed had several accomplices. By showing the suspect the names of 32 possible partners in crime and observing his reaction, agents narrowed their focus on the two named that elicited the most stressed responses.

"He displayed behaviors consistent with that he didn't like seeing those names on those cards," Navarro said. "We went out and investigated those two, and eventually they confessed and we convicted all three of them."

Theresa Sheridan, a 47-year-old attorney from Tucson, Ariz., said after attending part of the $1,699 two-day seminar called WSOP Academy, she began to realize that for the two years she's been playing the game, her unspoken body movements may have been her undoing.

"When I first started playing, my hands would shake," Sheridan said. "And I've controlled that. Now, Joe just gave me some good ideas about wearing a visor."

Stacy Kopacz said that now that she's been to three of Navarro's seminars, she's added reverse tells into her game.

In April, the 32-year-old Internet company president from Louisville, Ky., finished 10th at the World Series' circuit event in Indiana, after bluffing pro Mimi Tran off a hand.

"I just said, 'Same bet,' very nonchalantly and I leaned way into the table," she said. "One of the things Joe teaches is as someone's hand improves, the closer their physical hands will get to the pot."