Has Bernd ever tried to put couple of drops of cold water into his ear on purpose (not getting it there while showering, swimming, etc.)?
It's an interesting feeling, how the cold drops tickling the ear canal as they find their way inside. Then the water warms up in there and if let it flow out, it feel warm for the ear (probably the body is warmer in the depth of the ear canal).
Makes me think of how fluid consumption keeps a part in regulating temperature and we don't really pay it any mind. We drink a glass of water 5-10 C temp, that is warmed up by the body, which takes away heat from the body. Then the piss leaves at body temp. Or how the heat of a hot soup gets transferred to the body and that heat has to get rid off if outside temperature is also high, which makes us sweating.
Keeping fluid levels up in winter is most important. We are less thirsty in cold weather, so drink less, this has to be countered consciously. But for example if we are outside and relatively stationary (no heat produced from the work of the muscles), drinking cold water is a bad idea, dragging down body temperature.