Prostrations is a special Tibetan Buddhist Practice.  There are 2 different versions: the short and the long, in reference to the Ngöndro practice, we do the long version.

To do the prostrations we start we standing straight up and fold our hands at the heart center.  The two thumbs folded inside and kept the hollowness inside the palm, this signifies offering a jewel.  The left and the right hand together symbolize the true path of Wisdom and Method.  The hands then put on the crown chakra which represent the enlightenment quality of the Buddha, then on to the speech chakra which represent the teaching of the Buddha Dharma and lastly on to the heart which represent the Sangha; continue on to bow down on the floor with 5 points of body touching the floor: 2 knees, 2 hands, and forehead.  These 5 points of the body represents the five poisons:  ignorance, attachment, aversion, pride and envy.  With the short prostrations, once five points touched the floor, one must immediately come up, while in the long prostration, you slide completely onto the floor which represent an act of surrendering oneself – one ego to something bigger and better than ourselves that would help us purify, again once slide down completely, one must immediately come up as an act of coming out of Samsara.  Essentially, it looks like we are swimming on the floor.

Then Repeat.  I have heard people who have said that Ngöndro Prostrations become easier as we move along with the practice, I have yet to experience that.  Other than being part of Ngöndro, prostrations are used to show reverence to Divine Objects, many Tibetans have done prostrations throughout the arduous Kora journey at Mt. Kailash or from their home all the way to Lhasa.

One really important thing to note here, prostrations are not done for the Buddha.  That is wrong thinking, Buddha is not God of this world.  We bow down to purify all situations from the past where we did not respect others, for being interested only in our own satisfaction and did many negative actions.  Its purpose is total purification of our karma by turning ou mind, our body and speech and our heart to a bigger more meaningful purpose, that is of Enlightenment through the Buddha Dharma by the support of the Sangha and our teachers.