It's pretty simple actually. You have Clip A (your first clip) and Clip B (your 2nd) on the layer above A. You have Clip A on your timeline, not moving, just playing. Then, you keyframe the position of Clip B to slide in from right to left fairly quickly (like, 3-5 frames or so). The secondary motion is a little bit trickier, but it just involves doing softer less extreme moves afterwards with some easing on it, and throwing a bit of rotation in there. Make sure Motion Blur is turned on, and you're done.
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