I play KK like this: I 3-bet any pf raise, If I get 4 betted I fold (unless he has been way out of line). Dump the hand and go on. I have layed down KK to AA 5x in my past 150k hands or so (villian ended up showing in those cases).

A good way to get villian to show his AA, when you lay down KK is to type in the chat bar "laying down KK".