Kamasutra 5.5.32

5.5.32

mahāmātreṣvarāṇām antaḥpurāṇi niśi sevārthaṃ rājānam upagacchanti vātsagulmakānām/

But according to the customs of some countries there are facilities for Kings to make love to the wives of other men. Thus in the country of the Andras the newly married daughters of the people thereof enter the King's harem with some presents on the tenth day of their marriage, and having been enjoyed by the King are then dismissed. In the country of the Vatsagulmas the wives of the chief ministers approach the King at night to serve him. In the country of the Vaidarbhas the beautiful wives of the inhabitants pass a month in the King's harem under the pretence of affection for the King. In the country of the Aparatakas the people gave their beautiful wives as presents to the ministers and the Kings. And lastly in the country of the Saurashtras the women of the city and country enter the royal harem for the King's pleasure either together or separately.