Her hips and ass aren't moving an inch, but her waist is gyrating back and forth. It looks really bad, like she's been cut in half and the upper half is moving independently.
... I can't see what possible need there is for the onahole in this scenario.
I can't see what possible need there is for animation in this image. I thought the thumbnail looked decent but the separated torso jiggling and the mutation applied to that foot are horrific.