I think a key point of the Limerick is that it's supposed to be, to put it mildly, a bit off color! Rude, that is, or even downright crude...but funny. As Wikipedia explains....

The lim'rick packs laughs anatomical
Into space that is quite economical,
But the good ones I've seen
So seldom are clean,
And the clean ones so seldom are comical



Oh... and they often feature a young lady named Jill....but you'll have to Google it...I don't want to be thrown off the board! smile

G.