Little Jack Horner

Little Jack Horner sat in the corner
Eating his Christmas pie,
He put in his thumb and pulled out a plum
And said "What a good boy am I!"

The rhyme is about a masturbator named Jack.  Jack (as in jack off) Horner (as is horny) is in the corner, in isolation to concentrate on his task.  When he ejaculated (pulling out a plum), he was quite satisfied with himself.

Baa baa black sheep, have you any wool?
Yes sir, yes sir, three bags full!
One for the master, one for the dame,
And one for the little boy who lives down the lane.

The "wool" is semen.  The black sheep, or negro slave, overemphasizes his potency by referring to posession of three scrota.  His indiscriminate carnal desires have no opposing sense of decency to hold them at bay, as he seeks to deliver his loads to his master and family.

Diddle, diddle, dumpling, my son John,
Went to bed with his trousers on;
One shoe off, and one shoe on,
Diddle, diddle, dumpling, my son John!

The narrator is a despicable molestor and rapist whose own son must resist his father's diddling of his dumpling by wearing trousers to bed.  He even contemplates wearing his shoes all night long in case a speedy exit outdoors is necessary.

I love little pussy,
Her coat is so warm,
And if I don't hurt her,
She'll do me no harm.
So I'll not pull her tail,
Nor drive her away,
But pussy and I,
Very gently will play.

This one speaks for itself

i will never again be able to look at any nursery rhyme the same way. god damnit op.

Wee Willie Winkie runs through the town,
Up stairs and down stairs in his night-gown,
Tapping at the window, crying at the lock,
Are the children in their bed, for it's past ten o'clock?

It's ten o'clock.  Do you know where your children are?  Parents would do well to heed this rhyme's warning.  For Wee Willie, the perverted man-child, and his winkie are on the prowl.

Little Boy Blue, come blow your horn,
The sheep's in the meadow, the cow's in the corn;
Where is that boy who looks after the sheep?
Under the haystack fast asleep.

When he's feeling blue, the titular Little Boy gains his pleasures by "blowing his horn", a common euphemism for fellatio, with the local livestock.  After a productive day of "looking after the sheep", he is naturally very tired.

My milkshake brings all the boys to the yard,
And their like
It's better than yours,
Damn right it's better than yours,
I can teach you,
But I have to charge

This young lady makes an excellent milkshake, and would like you to know about it.  She would be glad to teach you how to make one, but you'll have to pay to cover the cost of the ingredients.

Mary had a little lamb,
little lamb, little lamb,
Mary had a little lamb,
whose fleece was white as snow.
And everywhere that Mary went,
Mary went, Mary went,
and everywhere that Mary went,
the lamb was sure to go.

It followed her to school one day
school one day, school one day,
It followed her to school one day,
which was against the rules.
It made the children laugh and play,
laugh and play, laugh and play,
it made the children laugh and play
to see a lamb at school.

And so the teacher turned it out,
turned it out, turned it out,
And so the teacher turned it out,
but still it lingered near,
And waited patiently about,
patiently about, patiently about,
And waited patiently about
till Mary did appear.

"Why does the lamb love Mary so?"
Love Mary so? Love Mary so?
"Why does the lamb love Mary so,"
the eager children cry.
"Why, Mary loves the lamb, you know."
The lamb, you know, the lamb, you know,
"Why, Mary loves the lamb, you know,"
 the teacher did reply.

This rhyme about chronic masturbation, and the consequences of getting caught, needs little further explanation after you realize the naturally blond Mary refers to her genitalia as her 'little lamb'.