You need to work on the jerkiness just like everyone said. I'm not in SFM right now but advance the scene forward a few frames using the hotkeys then rewind it back. Then keep repeating that to spot and jerky movements. Look up some tutorials too and see if you can pick up any tips.

http://kawaiidetectiveenthusiast.tumblr.com/post/135640746785/sfm-porn-tutorial-a-basic-animation

http://kawaiidetectiveenthusiast.tumblr.com/post/135704726155/sfm-porn-tutorial-2-reactive-motion