2.48 From that there is no disturbance from the dualities.
2.49 When that exists, control of incoming and outgoing energies is next.
We are getting close to the end of Book two, so the last few Sutras are what I would call a "wrap up". I talk a lot about the concept of duality and will do it more in future posts. The concept of duality cannot be separated from Yoga. It's the transcending of duality that leads to enlightenment.
Specifically related to the Yamas and Niyamas, these two Sutras states that when we have balanced out the ten qualities, our state of mind is free of duality. For instance, purity is the same as not engaging in vice. Engaging in peace is the same as contentment. In reality, there are only five sets of qualities, tow existing at the opposite ends of the spectrum. If your into math, that is the same as saying a negative of a negative equals a positive. I hate math, so I may be wrong on that.
So we apply this balance to the the three levels of action: thinking, speaking and doing. Then they also get applied to the five senses of sight, smell, hearing, tasting and feeling. Sutra 2.49 is speaking directly about the input and output of those senses. So, for instance, when we feel something, the natural result of that is a course of action on the three levels. First we think about it, then we may or may not speak about it, depending on the circumstances, finally, we have a locomotive response. Reflexes bypass the two higher levels. I mean, do you really want to have to think about weather or not you should move your hand away from a hot stove?
Have you seen pictures of yogis that sit on a bed of nails, or are able to puncture their bodies with spikes? It's a good carnival trick, but they have mastered the flow of information in their central nervous system, which can allow you to control pain. I have seen modern medicine poking into the concept of the mind and how it manages pain in our bodies. Don't go poking spikes into your cheek to prove you are some kind of badass. I suggest you read the book
which can help you if you want an alternative to pain management. It has helped me manage pain.