If you can't do it, and if you find it causes discomfort to stretch this far, well, obviously you are being disobedient and need to be strapped into the human equivalent of draw reins or some other type of leverage device, so that your body can be forced into this shape.
Doesn't make any sort of logical sense, does it? Why, then, do humans do it every day to so many horses?
It goes beyond bad horsemanship to force horses by mechanical methods that they are powerless to resist. No wiggling or self justifying needed.