Got to try that, the things Krishnamacharya used to teach those boys, no doubt for all the demonstrations they used to do. As with many postures and transitions (in the Advanced series for example, supposedly intended for demonstration only), practicing them daily would probably be too hard on the knees, joints but for the occasional demonstration, acceptable perhaps with enough training and preparation. Unfortunately these days, third is the new second and fourth the new third, many students are now practicing advanced postures daily, I wonder if this is wise.
Had to give it go, first side is just about OK but the second side a struggle, don't manage to get the foot high enough into the groin, cute party trick though, nice play a bit after such a heavy practice this morning.
Should also add that it's perhaps something to think twice about before trying at home as your messing with your knees. I've spent quite some time playing with the hands free getting into lotus and hop to lotus jump through,
And on a similar theme, the jump in and out of padmasana