Purity: Recommended Etiquette When Relieving Oneself
Practical Laws of Islam as per the teaching of Ayatullah Sistani
Ruling 75
When one is emptying his bowels and/or bladder, it is recommended that he sit in a place where no one sees him; and when entering the lavatory, to enter with the left foot first; and when exiting, to exit with the right foot first. Furthermore, when one is emptying his bowels and/or bladder, it is recommended for him to cover his head and to place the weight of his body onto his left leg.
-Ayatullah Sistani, Practical Laws of Islam, Purification (Taharah)