Yeah, so the guy who's fucking her is an asshole. I didn't even notice the slap until after making the gif. Hopefully she didn't mind, as she looks like she was doing really well, and probably didn't deserve it. Then again, maybe he knows something we don't.
Source: self (I actually captured this from a cheap video game)
File size: 6.8mb
Number of frames per loop: 67
Number of thrusts, bounces, or jiggles per loop: 11 jiggly thrusts, lots of jerks, one jerkish slap
