I learned this meditation during one of my recent teacher training classes, and I love it. In short you sit with your hands in lotus mudra in front of the heart, eyes open slightly looking at the tip of the nose, and whisper the following mantra:
Pawan, Pawan, Pawan, Pawan, Par Paraa, Pawan Guroo,
Pawan Guroo, Wha-hay Guroo, Wha-hay Guroo, Pawan Guroo.
There is something about whispering it that creates such a beautiful effect on the energy field. I feel such a unique vibratory effect and extension of patience in this meditation.
I highly recommend doing it along with Pavan Pavan by Guru Shabad Singh Khalsa for the full 31 minutes of the song, although the instructions are for 25 minutes.