Growing up in Maryland, I learned it this way:

Down by the banks with the hanky-panky
Where the bullfrog jumps from bank to banky
Saying eeps, ipes, opes, oops
Listen to the doorbell ring
I pledge allegiance to the flag
Michael Jackson sucks so bad
Pepsi-Cola burned his butt
Now he's drinking 7-Up
7-Up is bad for you
Now he's drinking Mountain Dew
Mountain Dew has no caffeine
Now he's drinking gasoline
Gasoline is made for cars
That's why he is so bizzare
Down by the banks with the hanky-panky
Where the bullfrog jumps from bank to banky
Saying eeps, ipes, opes, oops
Listen to the Keeerplop!

We sat or stood in a circle with each person's right hand palm-up on the next person's left hand, and each right hand would slap the next right hand. You were out if your hand was hit on "plop", and you could avoid this by pulling your hand out.