A literary device I've recently been getting far too much mileage out of, employing it in decidedly non-literary circumstances to draw tedious interlocutors into the delight of unexpected and sponteneous wordplay. For example:
"Even though it's available all year round, as far as seasonal drinks are concerned even though it's up against egg nog I still prefer cider."

...

"So, uh, you'd consider yourself a cider imbiber, then?"

(huh?)

"And, uh, if you quaff it down all the way to the pulpy dregs then that makes you...
a cider fibre imbiber."

(scowl)

"And, hold on, if the apples were from Afghanistan you'd be... (deep breath)
a Khyber cider fibre imbiber."

(thinly-veiled menace)

"Hot diggity! And if you were half-machine, concealing yourself within the body of a female, waiting for the right moment to strike, you'd be..."

(snaps, violently leaping across the table to throttle me into blessed silence, hysterically yelling)
"A CYBER-KHYBER CIDER FIBRE IMBIBER HIDER BIDER INSIDE HER!!"

If not the first, certainly the most outstanding appearance of this flavour of assonance occurs in Mark E. Rogers' The Sword of Samurai Cat, where Wisconscin Platt is heard to culminate: "And if it involved aerial combat in the cellar of a cartoon pooch it would be a dogfight in Auggie Doggie's dog of a Dog Ma dogma augment fragment basement."

Note: this is not assonance in the entirely conventional sense of the term, also exploiting scattered and furtive ashamed elements of rhyme and rhythm. More than the proximate device, I choose this term to describe my activities because it makes an veritable ass of me. Be warned, I consider any lull in conversation open season. Yessir, never a dull moment.