Your channel your ability to turn undead into your weapon.
Prerequisites
Channel Divinity (turn undead), Extra Channeling, any non-evil alignment.
Benefit
With a swift action, you charge your weapon with holy light. You can spend one use of your channel divinity ability to add 2d6 points of sacred energy damage to all your successful melee attacks against undead until the end of your next turn. This is a supernatural ability.