A doggerel is a light verse which is humourous and comic by nature – often viewed with disdain as containing little literary value. It can be considered to be children's light literature.
Doggerels might have any or all of the following failings:
trite, cliché or overly sentimental content
forced or imprecise rhymes
misordering of words to force correct meter
inept handling of subject.
Write a doggerel of 4-20 lines. You can have one or two long stanzas, or break the lines into smaller stanzas, your choice, but ... here's the kicker ... all of the lines must rhyme at the end. The best way to do that, is to start out with a word that has a gazillion rhyming words attached to it. Since this is a doggerel, there is no big issue about style or grace, just make it entertaining, and have fun with it.
Once upon an amber moon
I met a man in silver shoon,
Who tried to sing a bouncy tune
While sitting on a black balloon
And playing on a green bassoon
In the berry merry month of June
He bounced over a red dragoon
Who was untidy and roughhewn
And carried a maroon harpoon.
He tried to pierce the black balloon,
But luckily it was immune
To the attack of that buffoon
The man continued to croon
As he went into the blue lagoon
He suffered a bad mis-tune
When confronted by Neptune
Who whipped up a strong typhoon
To drown the man and his bassoon