The "slice of" link doesn't work.

But anyway, I'm reminded of one of my RP buddies. She's Italian, see, so English is her second language. Usually she's incredibly fluent (with a bigger functional vocabulary than most of the native speakers I game with), but one time she made an amusing mistake. See, she had a cold sore, so she told all of us she had herpes on her face.

After we calmed down from laughing our asses off, we told her that, while technically correct, that wasn't the sort of thing you go around saying to people, and suggested some less eew-inducing ways of saying it.