Maybe just one or two hot water bottles? [1] We use them in Winter to warm our feet in bed. But they are very versatile and can also be used to alleviate any kind of tension.
I also use one while I code: I put it inside of a small (baby-)sleeping bag wrapped around my feet. Sounds weird, but it's so comfortable!
I also use one while I code: I put it inside of a small (baby-)sleeping bag wrapped around my feet. Sounds weird, but it's so comfortable!
[1] https://www.google.com/search?q=hot+water+bottle&tbm=isch