1. A sexual procedure similar to the screaming seagull. In order to perform "the yeti," one must be doing a girl in the snow, and subsequently take a handful of snow, put it on her ham wallet, and pack it in with one's pork steeple. The audible result sounds like the call of the yeti.
2. The snowy bigfoot guy.
I was doing this chick on the ski slopes at Vail and I decided to give her the yeti. She groaned, and sounded like a yeti, which attracted a REAL YETI. It was frigging huge, and had horns and shit, so I had to ski away with my junk out.