Share 'disc under your knee legal?'

another is this legal question... Can you put a disc under your knee as when throwing.  For example, if your disc was ina bunch of dead pine needles/woodchips, you were in shorts, and had to go onto one knee.  is it legal to put a disc under your knee so you don't get a bunch of cuts?  If that is legal, how is it any different from moving your bag, or any other object under a foot to give you a b…