I could not care less

Turnoi mate; whereas 'couldn't is just a contraction of 'could not' you still must say 'I couldn't care less.' It's just one of those things old chum. The expression has been floating around the UK for hundreds of years, and eventually went to USA in the 1950's. However if you really want to spell it out aggressively 'I-could-not-care-less!' can be appropriate, but I've only ever seen you use it in the dismissive. It's an area for the native English speaker to get across to the student. Do you see?