To achieve super-smooth edges on both the crumb coat and final layer, hold a bench scraper in your dominant hand and then use the other hand to grip the turntable so you’ll be able to turn it as close to one complete rotation as you can. (If you’re right-handed, you’ll be rotating it counterclockwise and vice versa.) Begin rotating the cake and then gradually press the bench scraper up against the side, continuing to rotate at an even pace. Release pressure gradually while continuing to rotate the cake and scrape off the bench scraper. Continue until the desired smoothness is achieved. This step takes practice.