When you get sick, you should not indulge in the illness. Do not focus on the pain, thinking, “I’m sick. I have a headache. My tooth hurts.” That is indulging in the sickness. Pain and sickness just happen, and when they do, we cannot simply stop the sensation. Instead, we can rest, relaxing our mind and letting it settle in naturalness in relation to the essence of that sensation itself; there’s no feeling of displeasure or not wanting it, just looking at the essence of the sensation itself. In the sutras, this is called the foundation of mindfulness of feeling.