" 'You are 1st girl,' I told Constance.
'Yes, Master' she said. 'Constance is 1st girl,' I told her who had been the Lady Tina of Lydius.
'Yes, Master', said she who had been the Lady Tina of Lydius.
'Address her as Mistress,' I told the former free girl.
'Mistress,' said she who had been the former Lady Tina of Lydius, frightened, to Constance.
'Slave,' responded Constance to her, confirming the former free woman as second girl.
....
...the two girls, the blond and the brunet, first girl and second girl, yet both really new slaves, neither of whom had as yet even been branded."

Book 12, Beasts of Gor, page 135 ~¤~

"She was dressed, save for her bondage strings, in much the same way as most of the women of the red hunters, bare-breasted, with high boots and panties. Thistle, however, behind her, was naked, in a northern yoke and on a leather leash.
...
'We are going to pick moss and grass,' she said.
'That is good,' I said. 'Why is Thistle yoked?'
'It pleased me, Master,' said Thimble, first girl.
'Was she insubordinate?' I asked. 'She said a sharp word to me,' said Thimble.
'Did you switch her, too?' I asked. 'Of course, Master,' said Thimble.
'Excellent,' I said. Discipline must be kept in the tent."

Book 12, Beasts of Gor, pages 196 - 197 ~¤~

" 'How are her lessons in Gorean coming along?'
Sasi shrugged. 'I am teaching her as I can,' she said. 'Barbarians are so stupid.'
I had had Sasi, at the invitation of Ulafi, spend several hours a day tutoring the blond girl in Gorean. Sasi enjoyed this, standing over the blond girl with a strap, striking her when she made mistakes. When she had had a good session Ulafi would sometimes, when he thought of it, throw her a bit of cake or pastry, which she would gratefully receive. She would then kneel before Ulafi and kiss his feet, clutching the bit of cake or pastry. 'Thank you, Master,' she would say. She would then kneel before Sasi, her teacher, and offer her the bit of cake or pastry, which Sasi would take, taking most of it and returning a portion of it to her. 'Thank you, Mistress,' she would say, for Sasi was first girl. She would then creep to her cage, and be locked within it. She would lie curled up in it, a lovely, helpless slave, and try to make the bit of cake or pastry last as long as possible."

Book 13, Explorers of Gor, page 77 ~¤~

"It was natural enough, in the circumstances, for Tafa to have addressed Phoebe as 'Mistress.' As Tafa was currently subject to us, and Phoebe was with us, this put Phoebe in a position of de facto priority to her. For example, in a group of female slaves, for example, in a pleasure gardens, a fortress or a tavern, there will usually be a girl appointed First Girl. Indeed, if there is a large number of slaves, there are sometimes hierarchies of 'first girls,' lower-level first girls reporting to higher level first girls, and so on. The lower-level slaves will commonly address their first girl as 'Mistress.' Thus, in some situations, the same girl may be first girl to certain girls and be subordinated herself to another, on a higher level, whom she will address as 'Mistress.' Sometimes a hierarchy is formed in which girls are ranked in such a manner that each must address the girls above her as 'Mistress.' More commonly, it is only the lowest slave, usually the newest slave, who must do this with all the others, whereas the others will address only their first girl as 'Mistress,' and , of course, any free woman whom they might, to their risk, or peril, encounter. "

Book 25, Magicians of Gor, page 123