Mystery white mass in rat pee

Question
I have two little ratty boys.  About a month ago, I noticed
one of the boys was working on something in his private
area.  I came over to him just in time to see him pull
something white out of his little wee wee and eat it.  
After I squealed to my boyfriend in disgust and worry, my
boyfriend convinced me that he must have been just being a
guy, handling his own business so to speak and that I
should leave him be.
Well today, the same little guy was sitting with me on the
couch being scritched happily.  When he hopped off my lap
there was a little pee dribble (normal) and a white rubbery
looking pellet that looked EXACTLY like what he had eaten a
month before.  I have this thing (saving it to bring to the
vet).  It is milky-white, rubbery and solid.  
What is this?  Is this normal or does this point to kidney
problems?  Neither of the boys have shown any other signs
of poor health.  They run and play just as much as ever,
water intake has not increased, and he's not losing weight
(if anything he's a bit on the pudgy size... 30 grams
fatter than his svelte brother on the same diet).  Any clue
as to what this is?

Answer
Sometimes males will develop a penile plug. This is a build up of mucus
secretions from the male sex glands.  Sometimes it can actually build up and cause the rat to be blocked and cannot urinate properly causing discomfort.  Most cases though, healthy males will clean themselves and keep the secretions from building up.  I believe this is what you are witnissing.  It appears to be almost like hardend clear mucus, either transparent, opague or creamy (or milky) white.  


When the discharge becomes firm, it can plug the urethra, cause discomfort during urination as I stated above, and can stop the strong flow of urine, leading to a nasty infection as well.
Just keep watch that it doesnt clog up the little hole on his penis and be happy he is taking care of it like he is  supposed to be doing.

I know, these little ones can worry us to no end, so its always good to ask someone that may know just to save us from getting a few gray hairs we do NOT want!   LOL