Teddy KGB's tell was that when he had nothing and was bluffing, he would only break open his Oreo cookies, but not eat them. But, when he would have a winning hand, he would not only break open his Oreos, but he would also eat them. Such as when Mike suspects he has 4-2 for a straight, when the flop reads; 5 3 A, and Mike only has two pair, Aces and fives.