You possess an uncanny mastery of your magic, enabling you to modify spells on the fly much faster than others can.
Prerequisites: Spellcraft 12 ranks, ability to spontaneously cast spells.
Benefit: When you apply a metamagic feat to a spontaneously cast spell, the spell takes only its normal casting time.
Normal: Spontaneous casters applying metamagic must either take a full-round action (if the spell normally requires a standard action or less) or add a full-round action to the casting time (if the spell takes 1 full round or longer to cast).
Source: Complete Mage, page 46.