Actually, you really improved this piece. Yeah, there's some stuff that "could be done a little different" but... style vs quality. The bottom line is you're definitely coming along... (heheh yeah... said 'coming')...
A couple little points... First, I have to ask. Is he having fun? Or is he constipated? Being tortured? I don't know... I think about everyone (me included) missed his facial expression the first time through. We were probably... ahem... busy look at other things... dangling bouncing things... Yeah... nice tits and things... But I digress... lolz ... Seriously, I know "sex-face" is really difficult to get "right"... but even a maniacal grin would probably help this guy. XD
Second (and final) you might want to work a little on the movements of her legs. From the frontal view of her, every time he penetrates, she seems to kick her knees together and back kinda unnaturally (maybe impossible and even dangerous)... For a good (more normal?) motion, in this position, it's actually pretty popular to minimize his hip motions and put everything into her rocking forward and back. At the slap between them, mostly let her tits and hair/face express it. Hair and tits should probably move more or less in sync' since their both "dangly" in nature here... The face can "wince" with wrinkling nose, squint to the eyes, even maybe just a subtle (do something very slightly) with the lips...
Notice, since her legs are supporting, they probably shouldn't move much independently. Let them just maintain her bodyweight up at the level as she's pushed and pulled by him. The work on her ass and vag' is fine. You don't need to change that at all. She's stretched enough to receive dick, and the slap jiggles to a worthy degree to sell the thing.
Now, keep in mind, these are just suggestions. I'm not going to knock your anatomy... As I said from the start, "style"... It really does take all types to make the world go around. Some will be more popular than others, but that's just what it is being an artist... Fluidity comes with more and more cycles and loops developed so you can interchange some of the repetitious with other forms and variants of the same repetitious... I think that would help resolve the "robotic" nature of some of this. Over all, however, reckoning this is a loop, you've done the work really well. You are definitely improving, and I think anyone who checks out both can agree to the fairly dramatic improvement just for adding voice... Congrat's...
Now, don't forget to breathe, relax, and then keep on keeping on... :o)