Other mistake: The guys all go water skiing, towing the boat behind Peter's car. After Quagmire gets his penis bitten off the scene cuts to the hospital parking lot. Quagmire's car is parked next to Peter's. There would be no reason to go home and get his car instead of going directly to the hospital. (00:07:15)
Other mistake: When Stewie and Brian are riding on the train, Stewie tells Brian, "It's nice that the locals act as their own train crossings." They are seated on the left side of the train and looking out their window at this time. As the train passes, we can see the only person standing there is on the right side of the train. Neither Stewie or Brian could have seen him from the direction they were looking. (00:14:10)
Chosen answer: It's a real song called "Elvira". Originally by Dallas Fraizer in '66, however, this version seems to be the Oak Ridge Boys cover version. However, the mega lesbians skip the verse and just sing the chorus after the opening line.
Bishop73