languagelearning

Yeah, that's basically it. The standard term and only term I've ever heard personally is pølse i brød (as opposed to pølse i lompe), "kuk i kano" is just some colloquial funny term used in some areas. So you couldn't normally refer to bread as kano, it wouldn't make any sense, it's only in that set phrase that it works — obviously because of how a hot dog in bread looks like, you know, a phallus in a dugout boat.

I also found an old forum post where someone had claimed to have heard someone once refer to hot dogs in mashed potatoes as kuk i djupsnø, meaning "cock in deep snow", however I cannot find any attestations of this term aside from that forum post.