See 'Coldsore' and 'coleslaw'and 'herpes'. Slang for a juicy coldsore which looks like the unfortunate wearer has left some coleslaw on their lip.
1: "Excuse me, you have some coleslaw on your lip"
2: "oh no, that's just Dave, my coldsore"
1: "or coldslaw"
Both: "ha, ha, ha"