Proprioception
The sense of body position and force. The 'sixth sense' derived from muscle and joint receptors. Dysfunction common in autism and ADHD.
Proprioception is your sense of where your body is in space and how much force you're using. It's how you know your arm is bent even with your eyes closed, or how you can walk without looking at your feet. It's the internal map of your body.
When proprioception is impaired, you're navigating the world without coordinates. You bump into doorframes. You break things because you don't know how much force you're using. Or you crave intense physical input—crashing into walls, tight hugs, weighted blankets—because it's the only way to feel where your body ends and the world begins.