Bulging testicle

[DeweyTheHammy]

I am constantly checking Dewey [a syrian] for Wet Tail, even though I'm positive he'll never get it, you can never be too cautious...
Anyway, when I flipped him over today, I noticed that one of his testicles is a lot larger than the other one, and it wasn't like that yesterday. Its kinda bulging out a lot more than usual, and darker than the other. I don't have my camera with me, so I can't get a picture. Should I be worried?

[DeweyTheHammy]

Also, it doesn't seem to be bothering him. He's walking around like normal, I kinda prodded it to see if he would be upset but he just acted normal.

[souffle]

He is just likely a little warm. The testicles are really quite mobile and can move and bulge out in quite alarming ways. Dark eyed hamsters get increasing pigment on the testicles as they mature too.
The can get infections but these are not common and normally make them very sore and red and swollen.
I think he is just developing into an adult now really.