We would use heater packs slid down the trouser front when moving, and sleep with a hot Nalgene between the legs (which you drink the water / pee in it afterwards / rinse out in AM / repeat for next night).
Reads like a formula for crotch rot. :giggles
If the body's
core—heart, lungs, kidneys—and the large blood vessels in the neck are well insulated, the outer parts that are insulated will cool more slowly. This is where Gryph's layering is effective by creating air spaces that reduce the speed of heat dissipation. If the
core starts cooling quickly because it isn't insulated well enough and/or heat is being drawn from it by contact with wind or cold surfaces, how your gonads feel
might not be an issue because hypothermia and surviving your decisions created by cold-stupidity will be occupying your time. Having warm gonads at the time of death might be a comfort though.
:yippee:
Apart from body insulation, personal cold tolerance is a function of physical conditioning, genetics and attitude combined. Somebody with a heart strengthened by regular aerobic exercise is likely to be more comfortable in cold than others.