If you don’t have an actual rubbery hot water bottle use my method…
Grab a two litre pop bottle, turn the tap on full hot and wait until it’s steamy, carefully fill the bottle, cap it tight and wrap in a thin blanket. It’s super-easy, cheap, and works wonders. If you keep the bottle under the covers with you at night it will still be warm in the morning. Good for cold feet, cramps, stiff muscles, and general cuddling.
I keep a two litre bottle around just for my period cramps and bad foot circulation.
Be sure to NEVER drink anything from that plastic bottle again. The heat causes stuff to leech into the water from the bottle.
What other hot water bottle hacks do you guys have?