Oh dear! How embarrassing! Loosing one's loincloth while crucified. Now the poor girl is completely naked before the crowd. Well, it's her own damn fault, what with all that squirming about. To the spectators it might appear she's trying to lose her only covering, but for the girl it was an unintentional consequence of her body's physiological demand to squirm about in response to hanging from her arms with little support from her feet.Even Fit, Lovely Ladies Crucified can be a bit petulant. . .
"Bad enough they put me up here in this heat. I hate sweating in public. And couldn't they have found me a more attractive loincloth? This thing doesn't cover what it should, so what good is it? Ouch, now it's binding. Shit, I've got a wedgie, I'll bet the only wedgie in crux history! Maybe if I squirm against the stipes a bit. Grinding like a stripper. It's getting loose, looser. . . YES! There it goes.
"Now, will somebody please turn on the AC?"
Don't mean to quibble, but to have a wedgie there must be some fabric between the legs that gets pulled tightly in your ass crack. From what I can see there is no cloth between her legs, just wrapped around her hips, as revealed when the cloth drops away. That aside, she's a good actress and is made to look very sweaty, just like someone actually crucified would be while in a complete state of sheer panic and escalating pain from hanging on a cross. Her footrest is angled down so she really cannot stand at all. Remaining still would stress her hanging body tremendously and bring on fearsome cramping and muscle spasms in her tensed thighs, shoulders and arms. Hence, she has to dance about on the cross to whatever extent she can.
Unfortunately, there is no "rest" position on the cross. Every moment your body is enduring extreme discomfort. Moving about as she is only lets you temporarily alleviate the worst pain in one area but at the expense of increasing it in another. But constant movement is not possible. Eventually she'll tire and have to hang and endure with only occasional pushing up, bowing her body out, or moving hips to one side or another.
The terrified, frenzied movements shown by this actress and others can be sustained for a while when tied to a cross, but if someone is actually nailed I doubt such frantic thrashings about would be possible. The pain would be just too much, I would think. The major movement for someone nailed would be tensing leg and abdomen muscles to push up a bit--perhaps to the extent of bowing out from the cross--in order to breathe and relieve some of the worst muscle cramping and wound pain for even a short time. But everything comes at a severe cost. Pushing up with her legs may take some strain off her arms and ease the burning pain in her nailed wrists, but only at the expense of enduring heightened agony in her nailed feet and cramping her thigh muscles. I imagine someone condemned to die on the cross would find some intermediate position that balanced out the agonies coursing through her body with only small movements and tensing of certain muscles. Much of the time her muscles would be in spasms as shown in some of the videos here.