When you have reached a certain point in your development, you will realize opening your chakras is not feasible in certain location, people, time, or situation. If your chakras are constantly open, this will make you overly sensitive and you will feel energy being drained, and leaving you in a state of perpetual exhaustion. When you see the correct setting, it is ok to open your chakras, with good friends or family, or when you are ready to meditate. You can allow your aura expand outward, but when you are in a crowded area or negative place, you want to contract and pull your aura tightly around you. There is a difference between blocking and closing your chakras. When you are blocking, you are not letting positive or negative energy in, but when this happens it can cause severe physical, emotional, phychological, and energetic problems. Closing your chakra means you are still allowing the positive energy in, but the negative energies out. For example, when you close the window of your house because the weather is cold outside, and from the street noise but you also want to keep the heat inside and quiet inside the house. Closing your chakra, you are shielding your energy from being drained and not allowing negative energies to come in.
How To Protect Yourself
Every morning, before you go out, you can imagine an egg-shaped bubble protecting yourself. You can think the bubble as a golden light that surrounds you. By imagining this, your aura is being shielded. If someone is insisting on bothering you, you can cross your arms in front your chest to be protected. You can also lift your tongue up flat against the roof of your mouth to be protected from picking up any negative energies.