can't-can't
When you're trying to play a song and you fail miserably. For reference, the can-can is a well known dance, and band directors often have students play it.
"Wow, you played so badly!"
"Yeah, that was more of a can't-can't than a can-can, know what I'm saying?"
"Yeah, that was more of a can't-can't than a can-can, know what I'm saying?"