When meditating you can sense inside your body. For me it is easiest with a hand. Place your minds eye and focus on the inside of your hand, try to feel everything about the hand at once. What I sense is a sort of shimmer of vibrations or tingling sensation throughout the hand. The concept of the hand and shape of the hand dissolve into a formless fuzz of static.
Vipassana helps us hone this focus and bring it to all parts of the body. But what I’ve found is that if you look closely, you can actually do this with thoughts in the mind too. After all, that feeling of your hand literally is a thought in your mind in the first place!
When a formless thought arises, like what you’re going to do today, or a meeting you have, or a worry, or a memory. Look for the physical location and form of that thought in your head. Where exactly in the skull does it arise. What is it’s form and nature.
For me, most of these thoughts manifest as a tightening of an area of the mind. Like a small knot. The more stressful, the bigger and more complex the knot. But all thoughts seem to be a collection of feeling balled up in the mind.
Focus on that location, dig into the thought with radical acceptance, focus on it like vipassana tells us to focus on the physical body. What you’ll find is the same phenomena: the thought and all it’s baggage starts to melt, fade into mist, become static noise, formless, then simply dissolve into nothing, where you can rest your mind in the free fundamental nature of open awareness.