Shikantaza is a type of meditation that comes from Zen Buddhism. Basically, it involves sitting still and focusing on your breathing and your body sensations. You don't try to force any particular feeling or thought, but rather you let your mind be still and just pay attention to whatever comes up. It's like watching a movie in your head without trying to change it or react to it. The goal isn't to achieve any particular state of mind or reach enlightenment, but rather to simply be present in the moment and let yourself just be. Imagine sitting very calmly and quietly, without moving, and just enjoying being with yourself without any distractions. That's what shikantaza is all about.