I'm new to the FML, and I must say I have really enjoyed those limericks.
Here's my humble contribution:
 
There once was a ferret named Buster
Whose eyes had lost all their luster.
He was caught being bad
And was feeling quite sad
'Cuz he MUST have a raisin, he MUST-er!
 
Watch out-- I'm trying to think of one for Buster's big brother, Poncho.
 
Ferret-ly yours,
Denise, Poncho and Buster
[Posted in FML issue 1856]