Probably under my bed or in my dresser drawer. My drawer is full of clothes so I would be comfortable laying on the clothes and I could sleep sneak on the bed at night if there was no person there or when they're asleep. And then just sneak off when they wake up.
My sister still has her old dollhouse she got when she was younger, I'd probably use that. It would be quite a large space to live in by my little self, but will accommodate all my needs as a fairy. I'd be living the high life.