Is it cold out? Has your Heat Pump heating coil decided to break? If you have a Nalgene bottle (or just have one shipped overnight from Amazon), a sock, and a microwave or other method of heating water you’re in luck!*
*Ok, you’re not exactly “in luck,” but this might help you keep a little warmer at night. That picture should give you the general gist, but read on for some more pictures and explanation!Here are the components. A sock and a bottle. I didn’t try using it myself, but my wife claims it did a good job on her back keeping her warm in bed. I was glad to help. This would also most likely work very well when camping in cold weather.
Here’s how I heated up my bottle. I’ve read that these bottles can be microwaved, but haven’t seen this straight from Nalgene, so use your own judgment. It helps if you can put warm tap water in it initially, but I think I nuked it for around 3:30.
The other alternative would be to heat the water first and pour it in, but I’m sure you can figure that out. If you want to just buy something purpose made, this “Classic Hot Water Bottle” straight outta Germany looks pretty nice.