Saw a video on YouTube a couple of days ago of somebody bracing their hands behind their head as they dropped back into Kapotanasana (can't find the video now). Liz had suggested something similar a while ago but this seemed to go even further, not just having the hands over the head but really locking them there.
Just holding them there wasn't working so well, I would tend to allow them to drift out, locking them in was interesting though and I managed to catch my heels from the air.
Just about anyway, grabbed one (my left in the picture) but my feet and hands were sweaty by then and I slipped off off the right. Also when I drop back to the floor and walk in I tend to push my hips forward, this way my hips tended to come back and I couldn't work out how to get them forward again.
Interesting though and worth exploring a little more.
Found the video, bit different than I remembered it, the Kapo is a 1:24. Nice lift up to jump back too.