PrimaLoft?... whew! I was picturing my drink being chilled by floating cubes of musky Yak butter.... then my mind wandered to images of how Yak butter is sourced- several sets of cold, muddy, clammy Yak teats being yanked, my Yak grunting ( http://wiki.answers.com/Q/What_sound_does_a_yak_make ) furiously letting me…