up until age 3 my older dd would do her nightly raid into our bed--she would be so good at sneaking in we wold often not wake. When i was pregnant with our second dd , we started taking her back to her rom--she made quite the fuss then! What finally helped was one day, when we were having quiet time i explained to her that we all needed sleep and that mummy and daddy would be much less grumpy if we slept well at night. After that she didn't come in anymore!