Winter is coming, Mr. Stark. Over here at Casa Brown, that means it's time to break out the hot water bottles. Booyah. It doesn't get a lot snugglier than a down comforter with a little football of warmth lurking underneath it.
And there are so many other uses! Slap one on your back to loosen up a tight muscle; bring fuel to a watergun fight; or fill it with ice water in the summer and use it to cool down. (I'm sure you've got more—let me know in the comments.)
I've been around the hot water block, and I feel like Fashy, a German company, makes the best bottles; they hold heat really well and the stopper seals up extremely well. Add a wool or quilted cotton cover, the bottle works even better. (I have a well-documented Etsy addiction, so that's where I get mine.)
Yeah, yeah: There are more technologically advanced ways to bring the heat. Electric blankets, chemical pouches, even rechargeable bottles that use heating elements to keep their contents at temperature. I'm sure they're all grand. But, f that: Like a fireplace, you can't improve upon the old standard. The charmingly low-tech hot water bottle is cozy and unbeatable.