Bed Buddies
There’s your answer! Are you happy now!? ARE YOU!!?
Heh, that question got very popular after this journal http://humon.deviantart.com/journal/32744945/
Like Sweden would even know the answer. He is too busy covering up who he is sleeping with to notice what (and who) Norway and Denmark are doing. 
I also stumbled over this cute little cartoon written and voiced by a Norwegian and animated in Canada about a Norwegian and a Dane falling in love http://www.youtube.com/watch?v=iTef0HWbW_M&playnext_from=TL&videos=FNJ7DdlDuWU
Denmark Norway Sweden
12th June 2010