Herpe the Love Sore (S12E16)

Stewie persuades Brian to be blood brothers with him, but after they do it Stewie discovers he has got herpes and he must have got it from Brian. Some tough guys steal Peter, Joe and Quagmire's booth at the Drunken Clam. Word soon spreads all over Quahog, no-one respects them any more and Chris takes over from Peter as man of the house. (BBC)