The kissing one:

Joe and Lisa (or whomever)
sittin in a tree
K-I-S-S-I-N-G
first comes love
then comes marriage
then comes a baby in a baby carriage!
That’s not all! That’s not all! The baby’s drinking alcohol!

I heard a kid I babysit for sing a similar one:

Joe and Lisa sittin in a bush
All I hear is mush-mush-mush!
Lisa fall out, Joe saves her life
now I pronounce you husband and wife!


Oh yeah, I remembered another silly one:
He’s popeye the sailor man!
He lives in a garbage can!
Something something…