A Gorean slave girl in the presence of a free man or woman always kneels, unless excused from doing so. I had even learned to kneel when addressed by the guards and, of course, always, when approached by Targo, my master. A Gorean slave, incidentally, always addresses free men as "Master," and all free women as "Mistress."
Captive of Gor, page 73

At a gesture from my master I knelt. I did so in the manner in which I had been taught, back on my heels, back straight, hands on thighs, head high, chin up. I did not neglect a further detail. I spread my knees, widely. It was the position, of course, as I would later learn, of the Gorean pleasure slave. I had seen Eta naturally, unconsciously, assume it when she knelt. Such a girl, in kneeling, does not close her knees before a free man.
Slave Girl of Gor, page 77

"Is that how you will receive your master," I asked, "standing, like a free woman?"
Swiftly she knelt, in the position of the pleasure slave.
Slave Girl of Gor, page 404

"You will commonly," she said, not unkindly, "when kneeling before a free woman, keep your knees spread, unless your lady wishes otherwise."
"Yes, Mistress," I said.
"That is right," she said. "I find that good. But remember, the whim of the Mistress is everything."
"Yes, Mistress," I said.
"You are, as far as I know," she said, "the first male of Earth brought to Gor as a slave.
Fighting Slave of Gor, page 57

The position of the tower slave, in most cities, is very similar to that of the pleasure slave. The major difference is that the tower slave, whose duties are commonly, primarily, domestic, kneels with her knees in a closed position, whereas the pleasure slave, in a symbolic recognition of the fuller nature of her bondage, and its most significant aspects, kneels with them in an open position. The tower slave, of course, like any other slave, is fully at the disposal of the master, in any and every way. The distinction between the tower slave and the pleasure slave, though honored in some markets, some specializing in girls sold primarily for housekeeping purposes and others in girls sold primarily for the pleasures of men, is not really a hard-and-fast distinction; it is not absolute; indeed, it can even be transitory. A girl who is ordered to open her knees, or who finds them kicked apart, for example, realizes that she has now become a pleasure slave. Similarly a girl in one context may function as one kind of slave and in another context, as another sort. Serving a supper to a young man and his mother, for example, the girl may appear merely efficient and deferential. She kneels nearby, her knees closed.
Blood Brothers of Gor, page 107

She kept her knees tightly together before the free woman. Had she knelt before a man she would probably have had to keep them open, even if they were brutally kicked apart, a lesson to her, to be more sensitive as to before whom she knelt.
Magicians of Gor, page 18

"Incidentally," I said, "when you kneel before the free woman, in your carefully prepared modest garb, fit for a lowly slave, as you must soon do, to convey to her the message which will be inserted in the message tube about your neck, be certain to kneel with your knees closely together."
"Certainly, Master," she said. "She is a female, not a male."
Magicians of Gor, page 355

"The woman on the curule chair looked down upon me. I put my head down to the floor. The message tube then, on its throng, was on the floor as well.
"'Is that how you kneel before a free woman?' she asked. "'Forgive me, Mistress? I wept. 'The guards were about.'"
"'They are not about now," she said, 'and even if they were, it is I who am Mistress here, not they.'
"'Forgive me, Mistress!' I begged.
"'You will kneel before me demurely," she said.
Magicians of Gor, page 361