OK This is not a limerick.
Nor is it a limmerick [or limmmerick].
It starts out like one.
It is dragged out when one needs to explain the concept of "bastard thread"

There once was a fellow named Dick
Who was cursed from birth with a corkscrew prick
All his life was a fruitless hunt
To find a girl with a corkscrew c*nt
When he found one he dropped dead--
The G*d-damned thing had bastard thread.

[Usually taste would preclude such a posting, but it would seem to suit spaw's sensibilities...]