Texas is used after a natural 1NT or 2NT opening to show 6+ M and promise game values, but deny slam values. 

1NT/2NT as NT style:

• 4♦ - 6+♥;

• 4♥ - 6+♠;

• 4♠ - 5+♣ and 5+♦.

After suit or NT intervention, the convention is off.