Scot Dutchy wrote: Mine pop up and down the whole time and they often stay up. I always thought that was normal. In the sauna after coming out of the cold plunge pool everything disappears. Balls go up and my penis retracts. The water is pretty cold.
There are cremaster and datos muscles which pull up the testicles into the warm pelvis in response to cold and relax to allow testicles to drop away from the body in response to excessive warmth. This is because sperm production is affected by extremes in temperature and the body tries to maintain a constant temp. Too much heat in particular kills off sperm, which is why potential fathers are advised not to wear tight underwear or have excessively hot baths or showers.
So too, blood flow is regulated in response to temperature changes, altering the male anatomy accordingly.
But thanks for sharing your personal visual imagery Scot.