My yorkie sleeps with me. I have steps for her so she can and go as she pleases. Also depending on the size of your bed, it may be you who falls off. My last yorkie was only 3lbs but she took over the whole bed

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Many times i would find myself on the edge of the bed because she like to sleep right up under me. And as a member of the spoiled rotten club, I was not allowed to change my position so that she wouldn't be disturb

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I never worried about squashing her because if I rolled over on her should be sure to let me know or she would move so no worries there. What's really weird is even in my sleep I was unconsciously aware that she was in the bed. I guess it is something that develops over time.