There was a cute gal from Valhalla
---Wally
Big sheikh begged:"be my fourth wife, by Allah!"
---Wally
She said:"No, not quite
---Wally
can't wait every fourth night!"
---Wally
Still, he chased her to Walla Walla
---Wally

---.

---.
=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+
---.

---.

---.
When her pants came down,
---Anonymous
She maoned with a frown,
---Anonymous
"Since I now 'f____d' you.
---Anonymous
I guess 'fourth' will do.
---Anonymous
But, before we do 'four'
---Anonymous
DO me just once more! Oh boy, Oh boy."
---Anonymous

---p~~...~~

Any opinions on this limerick? I'll count to ten, before I react! ~ Wally
-------
He did her ten times and then she moved on to a horny rock star, who having retired temporarily, gave it to her three times a day until he knocked her up and sent her on her way.
-------
anon, your addition is OK as separate poem.First part is 5-line, self-contained Limerick--lines 1 & 2 must rhyme with 5; line 3 must rhyme with 4. Theme's often risque, but rarely pornographic. Second opinions?= Cy
-------
There once was a wannabe poet,
Had no talent at all, didn't know it.
But he gave it his best,
And ignored all the rest,
Tho' they asked him quite often to stow it.
...
The above is an example of an actual, if unkind, limerick. Limericks do tend to be more risque than the above, but are also known to be mocking as is that one.
Please note the rhyme scheme and form of the poem. There is no slant on the rhyme, because although slant rhyme is barely permissible, it detracts from the limerick due to the length of the poem.
Below is an older, fairly well-known limerick for your perusal to see a typical theme.
...
There was a pert lass from Madras,
Who had a remarkable ass.
Not rounded and pink,
As you probably think,
But was gray, had long ears, and ate grass!

-------
Some great comments here. Last one is terrific example of what a limerick is. Thank you all. ~ Wally
-------
I found this one quite amusing.