Legendarily naughty Little Johnny sat in class quietly as the students were composing a poem with their teacher. When she asked for an F-word that rhymed with "duck" he waved his hand feverishly.
The teacher frowned and passed him by. No kids, however, could offer her a solution. Finally she glared at Johnny and called on him.

Johnny put on his devlish grin and said, "An F-word that rhymes with duck is.... fluctuation."

The teacher blurted out, "No Johnny, that's sucks! I'm so sick of telling you what a little frigging asshole you are!"