The Chicago Tribune has dug deep this time: they sent a reporter to a farm and had him put lipstick on a pig. You can see the video here.
They tried it on 2 pigs. Only one of the pigs cooperated. The other resisted like lipstick was the kiss of death.
So when they say, "You can put lipstick on a pig," bear in mind it's only true half of the time.
Perhaps there will be a reportorial rush
to research how a possum looks with blush.