In the era of the Talmud there were no toilet facilities as we now have, and often people had to take care of their needs in the streets and in the fields. To preserve modesty, the sages determined a distance people must walk away from crowded areas before relieving themselves. The early sages (the Tanaaim) said that even one who relieves himself at night must go to a place suitable for use during the day, and darkness is no excuse for shortening the distance. The scholars asked: Did not a different sage suggest it would be appropriate for a person to accustom himself to taking care of his needs at night so that he did not need to go far away, implying that at night one need not go as far away as by day? The scholars also asked about an incident involving another sage, Rava. By day he would go up to a kilometer away, while at night he would ask his assistant to clear place for him in the city square (less than a kilometer away) so he could relieve himself. The scholars also brought as support for their question a different sage, Rav Zira, who would ask his assistant to check for people behind the study hall, because he wished to relieve himself there. All this implies that one need not distance himself as far by night as he would by day, in contradiction to the ruling by the early sages, which states that one must go as far by night as by day. Answer: The words of the early sages, who saw night as comparable to day, do not refer to distance but to the manner in which one relieves oneself. Just as one must relieve oneself with modesty by day and not remove all one’s clothes, so too at night. A different sage, Rav Ashi, gave a different answer. He said that it all depends on local conditions; if conditions allow relieving oneself at night without meeting anyone else, there is no need to go farther, but if conditions do not allow this, then one must go as far off by night as by day. The sages also suggested the manner in which a person should relieve himself. Before a person sits down he should massage his anus, and not wait until after he has sat. Massaging the anus after sitting will make him vulnerable to witches who may harm him. If a person sat and then massaged his anus, what can he do to save himself from the witches which might harm him? Answer: When he finishes relieving himself he should stand and say “Not for me, not for me; not tahim nor tahtim; [names of witches who harm those who massage their anuses after they sit] not these nor any part of these; neither the sorceries of sorcerers nor the sorceries of sorceresses!”
(Babylonian Talmud, Tractate Berachot 62a)