Whoa whoa we don't even talk about that! O.o Just ignore it!
what kind of stuff do u smoke guys?
This is an expression in English. I'm not sure about Norwegian.
Yeah, "elefanten i rommet" is also an idiomatic expression in Norwegian, and it's equivalent to the English expression.
And what means?
Wikipedia explains it well: https://en.wikipedia.org/wiki/Elephant_in_the_room