For all you who are concerned if the communication occoured before or after the snap, here is a play from Reddings that shows it's the play that's unfair - who says what to who when is not as important as the attempt to disarm the defense.

A22 pretends that he has injured an ankle, but refuses assistance when asked by the officials. During the following play he limps and does not directly participate. On the next play, A22 goes in motion with a very severe limp. At the snap, A22 runs without problems and catches a pass. Ruling: The unfair act provision should be utilized to enforce an minimum of a 15-yard penalty.

I couldnt find it in the rule book, but i did find it in the casebook... anybody have the exact rule?

The case play corresponds with the rule. (Same number)