Combustion is a phenomenon that occurs when a planet gets close to the Sun in the sky relative to our perspective here on Earth. When this happens, the rays of that planet get 'burnt' up by the Sun. This creates a hypersensitivity with the things related to that planet's energy.
This hypersensitivity brings about some irritability, touchiness and potential anger, but can also be a powerful catalyst to illuminate and purify that planet's energy (illumination and purification are qualities of the Sun). Especially if there are situations that revolve around power imbalances and the perceived abuse of authority (things related to the Sun), the combust planet will act out the hypersensitivity per its nature and disposition.
Mercury Combust gives touchiness related to communication issues Venus Combust gives touchiness related to respect issues Jupiter Combust gives touchiness related to moral issuesMars Combust gives touchiness related to strength and self-defense issuesSaturn Combust gives touchiness related to work and responsibility issues
Of all the planets, Mars is the most susceptible to combustion -- with an orb of 17 degrees. This means that for an average of about 45 days each year, Mars is combust. When it is direct (like this year), it will be combust for months. During that time, we are more irritable and touchy than at any other times. Also, we are much more willing to argue and defend our position, perhaps with a 'win at all costs' attitude.
This makes sense as Mars is the planetary energy of anger. Yet anger is the lower form of Mars, not its highest-developed quality. The higher Mars is the planet of discipline and willingness to suffer by putting our principles into action, not just talking about them, arguing about them, etc. His combustion will show a time of frustration and arguing that leads us to a greater awareness of how defending ourselves with anger is our real problem and the real destructive energy in our life - not the perceived threats from the outside we are trying to destroy.
Mars is also the part of us that likes to suffer, and feels thrilled by the rush of ego adrenaline that comes when we defend our causes. This adrenaline not only numbs us to the pain we are about to cause ourselves, it also numbs us to the pain we are causing another -- because after all, 'they had it coming.' Later we realize that maybe we were wrong. Maybe we jumped the gun and destroyed something we cared about, and maybe even another person in a rush to judgement. Especially personal relationships are susceptible now. Mars is the hasty, reckless decision-maker that destroys things carelessly, and then has too big of an ego and too much pride to admit it later.
Once we make a mistake with Mars combustion, a good apology (a true indicator of strength and courage) is powerful, followed by more yoga, discipline and meditation. Mars gives us the capacity to sacrifice our comfort in the moment for what we actually need in the long-term. For instance, getting up a little earlier to do our meditations and practices rather than staying longer in the comfortable bed (like the comfortable bed of elusive 'victories' for our 'causes').
Only recently has Mars become combust -- and it is joined a debilitated Sun, so we are especially prone to some irritable behavior for the next several weeks.
Anyone with prominent planets in Libra (Vedic Astrology) / Scorpio (Western Astrology) are especially at risk. Especially if the birth Ascendant, Moon and / or Sun or Nodes are in these positions.