Similar on guitar with bends I think. I feel like using the index finger is very awkward, I use the middle finger or ring finger (when what I'm playing allows it) rather than the index finger. Typically with the next finger behind to guide and provide stability/strength.
The proprioception on the index finger while bending on guitar is worse for me than locking the ring finger and using the wrist to control the magnitude of the bend. Useless backfill-ass finger.