Jack and Jill

Jack and Jill went up the hill
So Jack could lick Jill's candy
Jack was shocked when he got
A mouthful of cock
Because Jill's real name was Randy

I think this is the full version of that:
Jack and Jill went up the hill to smoke some marijuana,
Jack got high and dropped his fly and asked "Do you wanna?"
Jill said "Yes," and dropped her dress and then they had some fun
but Jill forgot to take her pill and now they have a son

But... Weren't they brother and sister?

"forgot"

Jack and jill went up the hill to fetch a pale of water jill forgot to take the pill and now they have a daughter

Jack and Jill went up the hill to fetch a pail of water
No one knows what happened there but now they have a daughter