Celestal

" I looked down upon her. 'You are a wanton slave,' I said. She looked up at me laughing, 'A girl in a collar is not permitted inhibitions,' she said. It was true, slave girls must reveal their sexual nature, totally. Do they not do so , they are beaten. "
Marauders of Gor, page 278

Slaves have sex, at anytime, in any place, with or without O/others present. This is because the Master wishes it.