The version I recall goes like this:

Down by the riverside hanky panky
Where the bull frogs jump from bank to bank
Singin' E-I-O-U your momma stinks and so do you.
Ping pong, ding dong, your daddy smells like King Kong
and plays with his Rubber Ducky Ding....... Dong!

It's the typical hand-slapping game where two children sit face-to-face with their palms outstretched, slapping back and forth. The "Dong" signifies that the game is over, and the last person who has slapped has won.

I was in grade school between 1986-1993 or so, in Southwest Florida.