Mordax et al

Bowing (single arm across the waist, bend at the small of the back) or curtsying (dip knees apart, arms slightly extended holding your skirt if one is present) are considered gestures of respect toward a monarch or politician of suitable rank on Derse or Prospit.

It is not common for Dersites of equal rank to bow to one another (or often even to bow to superiors in most situations) and except in the presence of the actual queen or king of Derse is usually only done by the excessively polite or is seen as a mocking gesture. 

In the presence of Dersite royalty make certain to address them as your Majesty (NOT your highness), and bow once upon greeting and once when you are dismissed- and once more if you are granted any special favors by the ruler. Any more will be seen as obsequious and overly servile at best, or mocking at worst. Do not under any circumstances ask the royals their names. If one of them tells you to kneel, I recommend a pause for clarification before you do so- but if you do kneel, do not rise until commanded. 

In Prospitian culture on the other hand it is fairly common for those of lower rank to bow to those of higher rank as a gesture of respect. Generally the protocol is for the lower ranking Prospitian to bow several times, and the higher ranking one to embaressedly request that they stop. As a Prospitian player, you will likely have people bowing to you left and right on the moon.

In the presense of the Prospitian royalty, you may follow the protocol outlined above for the Dersite royals, but either monarch will likely bow to you in return. I recommend keeping the exchange of bows brief to avoid becoming comical.