The posture that one takes at time of death is quite important. When dying, one should keep the same lying position as that of Sakyamuni Buddha when he went into parinirvana—head to the north, feet south, lying on the right side of the body, placing right hand under the head, pressing the right nostril with the right little finger and breathing through the left nostril. It is said in the scriptures that when lying on the right side of the body, breathing will naturally go through the left nostril.
Nevertheless, it is still important to block the right nostril. Whether being Buddhist or not, by taking the right posture when dying, one can be sure not to take rebirth in the three lower realms for the next one or two lives, even without the help of any other transference ritual.
~ Depicted from THE HANDBOOK FOR LIFE'S JOURNEY : On Death & Rebirth - How to Face Death