Why does one of my testicles hang lower than the other? No pain with this

That . That is a common and fairly normal finding, that the testicles may not be symmetric and one seems to lay lower than the other. As long as there is no associated pain or redness or discomfort, it is generally not anything to be concerned about. If you are a man between 15 and 50, it is probably also useful to do a regular testicular self exam, to get to know what your normal anatomy is like, and the testicles should be consistent and stable in size and firmness, and if one or both become larger or change in firmness, or even seems to develop a growth or mass, that is a different issue and probably deserves a medical evaluation.