uncommon bard enchantment metamagic 

Cast [F] verbal

You add a flourish to your composition to extend its benefits.

If your next action is to cast a cantrip composition with a duration of 1 round, attempt a Performance check. The DC is usually a standard-difficulty DC of a level equal to the highest-level target of your composition, but the GM can assign a different DC based on the circumstances. The effect depends on the result of your check.

Critical Success The composition lasts 4 rounds.Success The composition lasts 3 rounds.Failure The composition lasts 1 round, but you don't spend the Focus Point for casting this spell.

Core Rulebook, page 387.