there was a stage when I literally had to pin DS down to change his nappies, i'd sit infront of him and put my legs over his arms so he couldn't roll off. I know it sounds awful but he wouldn't be crying or anything, just relatively immobile, and I'd be as quick as possible of course, talking to him etc the whole time. Changing it while he was standing sometimes worked but even then he had to be entertained by something or he'd be walking off-and at the end of the day you can't change a pooey nappy when they're standing!