I actually had a Gorean Free Companionship and a "handfasting" which really at its simplist is drinking the companionship wine together. Of course just like any ceremony you can make it what you wish within the confines of the roleplay. It is usual to have a member of the Caste of Initiates to preside over such things but can also be performed by the Ubar/Tatrix etc.
My ceremony was saying some simple words in front of the Initiate, dressed in the caste colours of my companion (green caste) who was a Chief Physician, tying the ribbons symbolising the bonds of love and drinking the companionship wine.
There are a variety of ways to greet, The most important persons (rulers, warriors, caste leaders, men, women in that kind of order) go first and if at all the least important persons last (slaves).
The books outline a variety of different slave greetings ranging from Ho! Slut! to a simple Tal or totally ignoring their presence.
After all the slave can rightfully expect nothing from the free.
Another interesting fact is that the female companion is effectively giving herself to the man not as an equal but as someone only marginally more important that a true slave.
This varies with the location of Gor it is held and the man who you companion with. The books tell of several women who had status higher than that and kind of ruled the roost until "corrected" by their companion.
Companionships must be renewed every year in the books though in SL Gor it can be as little as 3 months or it lapses. Both parties can simply end the companionship at any time though the women can be slain or slaved at her companions choice regardless of who terminates the companioship. This though is extreme and it is more common that the woman will end up a slave before the end of the companionship.
For the record, I never ended up as a slave of any sort and my companionship lasted about 4 months and in SL Gor terms, that is a lifetime.
That was whilst I was alive however, though my demise came after I had really left Gor sometime, it changed me forever!