Strangler

The material below is Open Game Content from a 3PP Source

Strangler (Combat)
Throttling the life out of enemies is second nature to you.
Prerequisites: Dex 13, sneak attack +1d6, Improved Grapple, Improved Unarmed Strike.
Benefit: Whenever you successfully maintain a grapple and choose to deal damage, you can spend a swift action to deal your sneak attack damage to the creature you are grappling.