And here it is:
"If, however, in the opinion of the referee,
a player uses a deliberate trick in order to circumvent the amendment to Law 12, the player will be guilty of unsporting behavior and will be punished accordingly in terms of Law 12; that is to say, the player will be cautioned and an indirect free-kick will be awarded to the opposing team from the place where the player committed the offense.
Examples of such tricks would include: a player who deliberately flicks the ball with his feet up onto his head in order to head the ball to his goalkeeper; or, a player who kneels down and deliberately pushes the ball to the goalkeeper with his knee, etc. In such circumstances, it is irrelevant whether the goalkeeper subsequently touches the ball with his hands or not. The offense is committed by the player in attempting to circumvent both the text and the spirit of Law 12, and the referee must only be convinced that this was the player’s motive."
https://footballsci.wordpress.com/2013/05/01/fifa-laws-of-the-game-12-the-back-pass-rule/
Since the back pass rule was introduced to stop time wasting so the referee would (and should) immediately stop something like this. The heading strategy would clearly fall under "tricks". Yellow card (defender, gk or both) + indirect freekick to the other team.