Here is a Video of My Bun Umbreon as he enters his sleep house. Just a little introduction to Umbreon. [ame]http://www.youtube.com/watch?v=D30R73zLJ-4[/ame]
He is cute! Maybe he just does not feel the need to be inside. I know mine likes to go into his cardboard town mostly when he wants some peace and quiet and it's busy in our house. Your bun may just be very outgoing.