mg:
I'm a little confused by the idea that in a circle one person had a great idea..it was verboten to sing a parody of a song after the original had been sung, tempting though it may be. If you have a parody prepared then this is the ideal time to unleash it. A parody will only be understood by those who are Au fait with the original. So if you have a parody you wish to air (possibly for the first time) then it helps if someone in the circle has already performed the original. This means that the rest of the circle are aware of the song being parodied.
I speak as one who (in a 'filk' [sci fi music] circle) has heard a song (for the first time), and admitted to preferring the original, only to discover that I've just heard the original, and the song I was already comfortable with was, in fact, the parody!

Parodies (done well) are an art form in themselves, and will only work if the original is sufficiently well known that people appreciate the parody.
To write a parody, requires a good knowledge of the original, and so it can be taken as a compliment to the original.
See Yob In Hood
or the Who Writes Parodies thread

CHEERS

Nigel