Q, I agree with your statement of 31 Mar 07 - 02:11 PM , that the term 'coded' is not an appropriate term for the colloquial use of words and phrases in Blues songs and other songs.

It seems to me that "coded messages" should properly be limited to songs that contain words or phrases whose meanings were {are} purposely hidden from persons outside the group composing the songs because of probably physical retribution if the intended meanings of those words or phrases were known.

I believe this term doesn't fit the use of slang and other terms in Blues songs because there was {is} no fear of physical retribution if the more risque meaning of these slang words or phases became {becomes} known.

"Double entendre" seems to be a better fit for these words & phrases. I don't have another term which could be used in place of 'double entrendre'. "Songs with layered meanings" seems too labored and doesn't include the sense that many of these words have sexual connotations.

But I do have some thoughts on why those terms were used in Blues songs.

Fist, Here's a definition for "double entendre" from
http://en.wikipedia.org/wiki/Double%5Fentendre

{Sorry, Q. I know that you don't like Wikipedia}

"A double entendre is a figure of speech similar to the pun, in which a spoken phrase can be understood in either of two ways. The first, literal meaning is an innocent one, while the second meaning is often ironic or risqué and requires the hearer to have some additional knowledge. Although an expression made of French words, it is not correct modern French; the French use the term double sens ("double sense [or meaning]") for such phrases.

The risqué, often sexual, element is central to most people's understanding of what a double entendre is"..
-snip-

It seems odd that that definition limits itself to spoken phrases. What about "a word" [singular]? And what about other forms of communication besides the spoken word? Also, aren't there some times when a 'double entendre' word or phrase has more than two meanings?

But I guess that's nit picking...

I agree with the person who wrote the above quoted sentences that the hearer {or reader} has to have additional knowledge [of the cultural context] to fully understand the risque meaning of the words or phrase.

While society's moral code was probably part of reason why Bluesmen {and Blueswomen} used substitute words and phrases for sexual terms and sexual actions, I think that there's more going on than that.

The power of words and the creative {witty} use of words was {is?} highly valued in traditional African culture. I think that the use of these double {or triple?} entendre words & phrases in Blues songs is a carry over {carrying on} of this African Nommo spoken word tradition.

And more power to that tradition!