Jungle Love - S4-E13
Continuity mistake: In series 4 episode 13 Jungle Love: When the family are escaping the tribespeople, Chris is wearing the tribal clothing. When they jump in the plane there is a brief far-off shot of Chris wearing his usual cap and t-shirt. In a close up shot moments later, he is wearing the tribal gear again.
Jungle Love - S4-E13
Other mistake: In the kitchen when Peter is playing with the paddle ball and then Brian confesses to giving Chris the idea about joining the Peace Corp, there is a picture frame on the wall behind Peter. In this is various pictures of the family including Brian. In this, Brian is as a yellow dog despite being white in the series, and even in the scene depicted.
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