Many years ago when ex dh & I bought an old cottage that had no heating, apart from a fire in the sitting room, hot water bottles were very much the order of the day (night).
I remember going to bed one night, after ex dh and deciding that I would steal the hot water bottle that he had at his feet.
I was wearing socks in bed, as it was so cold, and stretched out my toes to grasp the neck of the hot water bottle.
Having got a grip, I started to tug on it, but it didn't move!
I tugged more, but to no avail, so then I lifted the edge of the duvet to find that I had firmly grasped the neck of our Jack Russell, who had burrowed down to the warmest spot in the bed!
The look on her face was beyond description.