Here's an excerpt of my latest cocojams2 blog post http://cocojams2.blogspot.com/2014/11/a-biscuit-phrase-in-playground-rhymes.html "A Biscuit" Phrase In Playground Rhymes (Examples & Its Possible Source)

"A number of playground rhymes include the refrain "a biscuit" or a folk processed form of those words. As a result of my curiousity about the source of that "a biscuit" phrase in those playground rhymes, I've come up with the theory that the "a biscuit" refrain is a folk processed form of the words "a trisket". The words "a trisket" words were popularized by the Jazz song "A Trisket A Tasket". That said, from the rhyme examples that I've found, it appears that the "a biscuit" refrain wasn't included in "Down Down Baby" and other rhymes until the 1970s. And rhyme examples that mention "Ronald McDonald" couldn't have been created before 1963 when that McDonald's mascot was first created. http://en.wikipedia.org/wiki/Ronald_McDonald.

I'd love to know if anyone remembers chanting a rhyme with "a biscuit" used as a refrain prior to the 1970s.

My guess is that when they are used as a refrain, the words "a biscuit" may not have originally had anything to do with the food named "biscuit". That said, in some "a biscuit" refrain rhymes those words appear to refer an actual "biscuit"- for instance in some examples of those rhymes the lines go: "I have a boyfriend/a biscuit/He is as sweet as/a biscuit".
-end of quote-
Notice that the example given below omits the word "as":

"I've got a boyfriend, a biscuit/ He's so-oo sweet, a biscuit".
-snip-
That cocojams2 post contains fifteeen examples of "a biscuit" refrain rhymes. Here's a rhyme example that I didn't include in that post:

"I can only remember the down down baby one, our version went like this

Ronald McDonald, ooh ahh a biscuit
Ronald McDonlad, ooh ahh a biscuit
A-shishi-wa-wa, a biscuit
I've got a boyfriend, a biscuit
He's so-oo sweet, a biscuit

Sweeter than an ice-cream, cherry on top
Sweeter than an ice-cream, cherry on top

Down down baby, down down the rollercoaster
Sweet sweet baby, I'll never let you go

Shimmy shimmy cocopop, shimmy shimmy wow!
Shimmy shimmy cocopop, shimmy shimmy pow!

I can't believe that I remember all that!!"
-mal'occhio http://www.essentialkids.com.au/forums/index.php?/topic/845958-hand-clapping-games/ "Hand clapping games", Posted 18 November 2010
-snip-
...By the way, what's the earliest documented date for any "Down Down Baby" ("Shimmy Shimmy Co Co Pa") playground rhyme? "Shimmy Shimmy Ko-Ko-Bop" by Little Anthony and the Imperials was recorded in 1960. But that rhyme doesn't have anything to do with being "down by the roller coaster" or having a boyfriend (or a girlfriend) who was sweet "like a cherry treat" or "as a biscuit"). Were there "Shimmy Shimmy Coco Pa" (or similarly spelled) rhymes before 1960?"