The other night/early morning at 3:30 I was sat downstairs after having a BM just before bedtime feeling really miserable and wishing the throbbing would go away. (I was sat downstairs as my constant tossing and turning and sharp intakes of breath, ouches etc were disturbing SWMBO)
I wondered what I could use as a heat source, we have no hot water bottles. I eventually got a plastic cola bottle filled it nearly full of hot water (being careful not to use water too hot) and wedged it gently between my bum.
It actually seemed to work!!!!! I was able to go to bed shortly after!

hey del,
i once did that to, and it did seem to do the job. i went and got a good neighbour of mine to buy one of those smaller heat pads, the kind of thing you get for knee , calf injuries, or neck. it cost about 17 pounds uk sterling. that work well very well,
i also had heat pads you put in microwaves, but they only lasted around an hr nd half or so.
yup i think everyone on here has tried there own homemade gadgets etc @ some point.
wishing you well