Character mistake: Lois says to Quagmire, if you have any questions we'll be right across the street. They live next door obviously, not across the street.
Factual error: You cannot get paternity test results back in one day. It takes 3 to 5 days or even weeks depending on the lab.
Continuity mistake: Peter is sitting on the couch talking on the radio. You see the phone sitting on a table beside the couch. But when Peter picks up the phone to call Quagmire, the phone is right beside him, without him ever moving it from the table.
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