Taunting the fans?

[referee99]

Looking for feedback (Fed Rules) relating to player interaction with fans.

In the Oakland Athletic League, just prior to the playoffs Player X quits Team A, has a residence change and is allowed to play for Team B in the playoffs!

Of course the two teams match up in the first round of playoffs. Team A (who lost the player) coach suggests he'll pull his team off the floor... unfair advantage... etc, but come game time its a go.

High intensity environment, packed gym. I am a spectator. Player X gets booed every time he touches the ball. He does well in the game, and after most baskets, gestures towards the opposing fans.

No penalties assessed for this behavior. Would you/ should you?
In addition, other players would cock an ear to the crowd, or give them the 'ssshhh' indication after baskets or free-throws.

What do you find acceptable in this area, and what has to be punished? Any rules interps would be helpful.