Replying to Park skiing from a skiers point of view

So i am having this debate with my parents about park skiing. They do not understand how it is possible for someone to know how to ski properly if they do not have a coach. They keep saying i am doing stuff wrong and do not know how to properly "twist" in the air or on the rails since i did not have proper training. This aggrivates me because its something u pick up by skiing and watching others do it too. I know what im doing and know the ways to do each trick on and off snow. However they are still not understanding me. Help me out NS, what should i tell them or show them to shut them up and make them understand that u dont need training in park skiing to know what u are doing.