From all the information I have seen this would be enforced just like a holding foul or any foul against a player. The following is taken from one of the bulletins sent out by RR.
"In trying to have a strong impact on such player behavior the committee in 2010 made an important change that will take effect in 2011. Beginning this season, unsportsmanlike conduct fouls by players will be treated as common fouls, in the sense that the penalty will be enforced the same as if the foul were holding or a block in the back or any other common foul. If the ball is alive when the player makes the taunting gesture, then the penalty is enforced at the spot of the foul—and the key outcome: no touchdown. One way to think about this is that starting in 2011 such a player will have a choice: he can score the touchdown, or he can taunt the opponent—but no longer can he have it both ways."
