Both of dukes were dropped when I got him at 12 weeks. My g/f made a comment that they looked smaller, so I checked and only felt one - him and duchess had been playing pretty hard prior, so not sure if that has anything to do with it. Then in the morning they were both down again. Odd?
Oh yeah !!! I'm definitely an expert on "NUTS" Chum's lol , anyhow, Testicles are temperature controlled, They draw closer to the body in cold weather, example cold water, to warm the "Swimmers", yep that's a good term, and the warmer it is outside, or in the shower, the Testicles cool off by getting further from the body, The "Swimmers" are allowed to cool off. In my opinion, if the testical has truly dropped, Unless your checking him after a cold bath, or in cold weather, or in a refrigerated room, then their may be a problem, and i'd consult your vet.
Booger's balls dropped all crooked and weird; one is significantly smaller, and behind the big one. The vet wasn't concerned because they dropped, but he does get made fun for it quite frequently. By me, of course.