You can loose your breath weapon with but a thought.
Prerequisites: Con 19, breath weapon with recharge time expressed in rounds.
Benefit: Using your breath weapon is a swift action. When you use this feat, add +4 to the number of rounds you must wait before using your breath weapon again.
Special: You cannot use this feat and the Maximize Breath feat on the same weapon at the same time.
Source: Draconomicon, page 73.