Without getting this post removed I'll try and answer. The reason testicles are in a sack away from the body rather than inside the body is that they operate best at 36C as opposed to 37.5 for body temprature (why I have no idea), Therefore a significant and regular drop in temprature may mean that are not working at their optimum temprature. However at these times the testicles themselves move up closer to the body to try and maintain the correct temprature.