It's like what porn would be like if Tetsuro Araki directed it; in particular, I kinda just remember that one sequence from Death Note where Higuchi lays Misa in his car.
[It had plane sounds effects and everything... you know... to make it more hilariously intense]
I mean, the above GIF even simulates the shakey-camera look you tend to see in Araki's work; and the final part of the GIF reproduces this neat effect where it seems like the camera is traversing around the geometry of the characters in the frame (which you also see in Araki's work; look at the part where Light first uses the death note; the intensity of the super-zoom shots is not due to a pan... it's due to the act of physically animating Light towards the camera); the subtlety of the animation in the above GIF allows the penetration to seem more intense since it makes it seem like there's a better sense of 3-dimensional space by way of how it follows that particular action of insertion; it almost feels like the camera motion was attached to the guy's hips.
ANYWAY, I was so impressed by this GIF [it's remarkable, really] that I actually intend to get this thing on DVD; maybe they'll have it at Rasputin's and I'll pick it up when I get the Maltese Falcon and Double Indemnity.
Now, while I might seem to be blowing up this GIF's awesomeness, there are, apparently, a lot of prolific animators that work in hentai... sometimes under aliases... sometimes not (in Crimson Climax [Hotaruko], Satoshi Urushihara and Yasuomi Umetsu did some animation, for example... or, at least, this is what I remember being told over at animpages daily).