Always remember to give thanks to the birds . . . before you steal their food.
If you find the secret settings that control split shutter speed mode in your camera, making the left side of the frame fire at 1/500 sec (or faster) and the right side of the frame at 1/100 sec (or slower), you can achieve back end blur like this. Wait a minute. “Is that the same model from yesterday?” Oh. Strike out the first sentence. Never mind.
This is what happens when you try to save 5 peanuts on the model agency fee. It’s the, “OMG! – What do I do now?” blur.