Sometimes Yin and Yang are easy to understand: Where is the most Yang place on your body? The top!
The uppermost point on your body, Du 20 (aka Baihui, aka “Hundred Meetings”), has everything to do with Yang.
We use this point either to send excess Yang back down, or lift deficient Yang back up. Excess Yang might show up as dizziness, headaches, confusion, or anxiety. Deficient Yang can include physical prolapse, or a general sense of feeling heavy, or low-energy.
This point is known for waking up the mind when needed, and also for calming the mind. The Du channel travels up the spine into the brain and has a branch that goes through the heart, so when there’s agitation that’s felt both in the mental process and the emotions, this point can offer welcome help.
Two other specific times I use it:
One, for cases of low back pain, especially felt right in the spine. If you have pain in your spine, try pressing on this point (or right in front of or behind it, if one of those spots feels more tender or sensitive). You can press the point while rotating your hips, picking your knees up, or stretching gently, to bring your body’s attention to the low back.
Two, for nasal congestion. The Du channel continues on from Du 20 to the nose, and I’ve seen it help dramatically with nasal congestion.