Body doubling means doing your task while someone else is present and working too, either in the same room or over a video call. You are not collaborating, you are simply borrowing a sense of accountability and shared focus. For many people with ADHD it makes starting and staying on task dramatically easier.
You can recreate the effect in several ways: a friend on a silent call, a coworking or focus room, a virtual study stream, or even a timer you commit to out loud. The presence of another focused person turns an abstract intention into something you actually follow through on.