The sit down is just for leg strength, to exaggerate the body coiling/folding for training purposes, and to hint of where you end if you stepped on someone's knee, and kept going down until you land with your weight on it.
All the dragons ive seen are basically just two forms: weight forward-ish with back hand ahead of the hips, and weight straight down with the back hand at the hips of even behind them. One has forward energy, going in and down (for going forward and crashing into something), and the other one is going down and back (in case the other person is going into your space).
Man carcass in alley this morning...