There are a few things you need to know if you want to alleyoop in NBA 2K18 for Xbox One. First, make sure your court is level and have a good spot to hang on the backboard. Second, use your agility and quickness to jump up and grab the ball before it goes out of bounds. Finally, be sure to stay focused and don’t let your opponents get too close - they can block your shots or rebound the ball for a layup.