Though it's true orign remains unknown, it is known that this term was coined in Canada, derived from a bible camp t-shirt.
This phrase is used as an exclaimation to a confusing, ridonkulous situation. It is the next tier up from wtf.
Extra "cuh"s can be added to increase the intensity, thus implying a stutter.
Cindy: "Kay man, I don't know. Wccf?"