Dexterity in Charisma

Every day you can add your charisma modifier to your dexterity modifier in a dexterity or charisma check or save equal to the number of your proficiency bonus. 

Also you can add your charisma modifier to any attacks that use dexterity while you are using a dexterity based weapon or a bardic instrument.

When you take this feat twice you add your dexterity and charisma mod to any dexterity or charisma checks or saves at will.