Restrictions

A restriction placed on a kajir can be for many reasons... punishment, training, but it is common for it to be done purely for selfish reasons.

Friends of her Master will often bring Their own girls with Them, in visiting, and with these, after the Men have been served, she may make friends, perhaps chatting in the kitchen.These girls may be exchanged among the Men, but commonly they are not. Most Masters are rather possessive of Their slaves, particularly if They are fond of them.
~Guardsman of Gor, page 209~

"Please Master," she said "Take pity on me. Take pity on the miserable needs of a slave girl."
"you are not Mine " I told her, " you are a pretty little thing, but I do not own you."
"Please," she said.

"Your Master," I siad, " if he chooses, will satisfy your needs. If He does not, He will not." For all I knew she might be under the disipline of deprivation. If that were so I had no wish to impair the effectiveness of her Masters control over her. Besides I did not know Him. I did not wish to do Him dishonor whoever He might be."
~Beasts of Gor, page 49 ~