To the Pain is a trait in Destiny 2 that can appear on 52 weapons. An enhanced version exists on crafted and some newer weapons.
What To the Pain does
While this weapon is equipped, taking damage increases handling and aim assist until the weapon is stowed. Taking more damage increases the effect.
Enhanced version
While this weapon is equipped, taking damage greatly increases handling and aim assist until the weapon is stowed. Taking more damage increases the effect.