It is narrated from Sayyiduna Abu Hurairah, may Allah be pleased with him, that the Messenger of Allah, peace and blessings be upon him, said: "Whoever applies kohl should do so an odd number of times; if he does, it is better, and if he does not, there is no harm. And whoever performs istinja with stones should do so an odd number of times; if he does, it is better, and if he does not, there is no harm. And whoever eats food should use a toothpick, and if something comes out from the toothpick, he should throw it away, and if it sticks to his tongue, he should swallow it; if he does so, it is better, and if he does not, there is no harm. And whoever goes to relieve himself should conceal himself; if there is nothing to conceal him except a heap of sand, then he should sit behind it, because the devils play with a man's private parts. Whoever does so, it is better, and if he does not, there is no harm."