An explnation for the form of the Double-dactyl
with thanks to onone and to this helpful site:

A dactyl is three syllables with the emphasis on the first syllable. A double dactyl is two of those together (BUM-bum-bum BUM-bum-bum). There are some words out there that are double dactyls (invisibility, extracurricular, verisimilitude, for example).

A double dactyl poem has eight lines. Lines 1, 2, 3, 5, 6 and 7 are all six syllables with the emphasis on the 1st and 4th syllables. Lines 4 and 8 are both four syllables -- a dactyl plus an extra (BUM-bum-bum BUM!) and these lines rhyme.

And then there are some specifications about what goes in each line.

Line 1 is nonsense -- higgledy piggledy, or whatever you feel like making up!
Line 2 is a name or proper title -- Boromir Steward's Son
Line 3 is whatever you want (six syllables)
Line 4 is whatever you want (four syllables)

Lines 5, 6, and 7 can be whatever you want, but ONE of them has to be one word that's a double dactyl.
Line 8 is whatever you want, but generally has a kind of twist to it, like a lymerick's ending. Line 8 also rhymes with line 4.

Is that more than you ever wanted to know? Wink I love them! For me it's just a matter of finding the right words and putting them in -- a little like a cross-word puzzle. - onone