It is narrated from Hazrat Abu Hurairah (may Allah be pleased with him) that the Noble Prophet (peace and blessings be upon him) said: Whoever applies kohl should observe an odd number; if he observes it, it is very good, otherwise there is no harm. And whoever performs istinja with stones should observe an odd number; if he observes it, it is very good, otherwise there is no harm. And whoever eats food should throw away the toothpick and swallow what has been chewed with the tongue; if he observes it, it is very good, otherwise there is no harm. Whoever goes to the toilet should observe covering the private parts; if he finds nothing except a mound, he should turn his back towards it, because Satan plays with the private parts of the children of Adam; if he does so, it is very good, otherwise there is no harm.