A danceplanation is when a person is telling a story or explaining a concept while raising and waving their arms all over the place. At the same time they'll shuffle their feet and occasionally throw a small kick in front of themselves; but, kicking isn't mandatory. In extreme cases both feet may come off the ground.
You should have seen Bob's face when his girlfriend confronted him about that girl he was talking to at the bar. He was giving quite the danceplanation.
Jim, two hours late to work, was giving quite the danceplanation to his boss as to why he didn't have the all the reports written and turned in on time.