Well 1st i read Kelis's explanation that it was whatever a woman had that attracted men, but then i read that i refered to a hand job, the latter sounds more fitting with the words i think!
I carefully watched the video in order to try and discover what Kellis meant exactly by Millkshake. I pretty much concluded it meant sex appeal meets technique given the huge amount of sexual symbolism in it (which I found very amusing lest ye think me a prude)..
It does amaze me that in the US oops you see Janet's nipple and you sue for being so offended yet many of the US singers are basically lapdancers who can sing and they don't seem that bothered by that!