[MereInterest]

In the spirit of inquisition, which "l" do you consider to be the extra one?

[StavrosK]

They're both about the same, but considering that "cl" is a sound by itself, I'd go with fuster cluck.

[troels]

Also, removing the "l" from cluck would leave you with a word that still sounds obscene, making the whole process pointless.

[arielm]

+1

[socceroos]

I generally use spoonerisms in the sense of the first 'sound' of a word.