Adding an o-ring to your wacky rig means you don't have to stab your stick worm through the body. Doing that weakens the bait and you're likely to lose it after one or two fish.
Use with a wacky rigging tool to easily and effectively wacky-rig your worm and stickbaits. By sliding an o-ring onto the worm and slipping your hook under the ring, you'll still get that full-body flapping motion and balanced fall that makes the wacky rig so awesome, but you won't harm your bait. As a bonus, an o-ring connection means there's no soft plastic filling the hook gap.